🔹 TOEFL Speaking Task 4 (Lecture-Only) Template
In the lecture, the professor discusses [topic], explaining that it involves [collocation + collocation].
Firstly, he mentions that [topic] is connected with [collocation + collocation]. Moreover, he provides an example to show how [topic] relates to [collocation + collocation].
Secondly, the professor points out that [topic] occurs because of [collocation + collocation]. In fact, he emphasizes that [topic] can be better understood through [collocation + collocation].
So after listening, I now have a clearer understanding of [topic].
🔹 Environmental Science
21. Greenhouse Effect
The professor goes into a ton of detail about the greenhouse effect, which is the process where gases trap heat in Earth’s atmosphere. After introducing the concept, the lecturer explains that carbon dioxide and methane absorb infrared radiation, warming the planet. The first case shows climate change because of rising emissions and energy consumption. She goes on to say that another example is agricultural activity. For instance, livestock release methane because of digestion and waste production. In fact, the professor emphasizes that while the greenhouse effect is natural and necessary, human activity intensifies it. This leads to melting glaciers, rising sea levels, and shifting weather patterns. So after hearing this lecture, I now have a better understanding of the greenhouse effect and its impact on climate.
22. Ozone Layer Depletion
The professor goes into a ton of detail about ozone layer depletion, which is the thinning of Earth’s protective shield against UV radiation. After introducing the issue, the lecturer explains that chlorofluorocarbons, or CFCs, break down ozone molecules in the stratosphere. The first case shows danger because of ozone holes and radiation exposure. He goes on to say that another effect is harm to living organisms. For instance, skin cancer rates increase because of UV rays and weakened protection. In fact, ecosystems also suffer, since UV radiation affects crops and marine plankton. The professor highlights that international agreements like the Montreal Protocol have reduced CFC use. So after hearing this lecture, I now have a better understanding of ozone depletion and global efforts to solve it.
23. Renewable vs. Non-renewable Energy
The professor goes into a ton of detail about renewable and non-renewable energy, which are two major sources of power production. After introducing the idea, the lecturer explains that renewable energy, such as solar and wind, can be replaced naturally. The first case shows sustainability because of clean resources and low emissions. She goes on to say that another type is non-renewable energy, such as coal and oil. For instance, fossil fuels provide abundant power but cause pollution and resource depletion. In fact, the professor emphasizes that the future depends on transitioning to renewable energy to reduce global warming. Governments and industries are investing heavily in this change. So after hearing this lecture, I now have a better understanding of the benefits and drawbacks of energy sources.
24. Acid Rain
The professor goes into a ton of detail about acid rain, which occurs when pollutants mix with water in the atmosphere. After introducing the process, the lecturer explains that sulfur dioxide and nitrogen oxides from factories and cars combine with moisture to form acidic precipitation. The first case shows damage because of soil acidification and forest decline. He goes on to say that another effect is harm to aquatic life. For instance, lakes lose fish populations because of low pH and toxic water. In fact, acid rain also corrodes buildings and historical monuments. The professor highlights that controlling emissions is essential to reduce the problem. So after hearing this lecture, I now have a better understanding of acid rain and its environmental impacts.
25. Deforestation
The professor goes into a ton of detail about deforestation, which is the large-scale removal of forests for human use. After introducing the problem, the lecturer explains that logging and agriculture are the primary drivers. The first case shows harm because of habitat loss and species extinction. She goes on to say that another consequence is climate change. For instance, fewer trees mean less carbon absorption because of reduced photosynthesis and increased CO₂. In fact, deforestation also disrupts rainfall patterns and soil quality. The professor emphasizes that reforestation and sustainable land management are necessary to restore balance. So after hearing this lecture, I now have a better understanding of deforestation and its global effects.
26. Desertification
The professor goes into a ton of detail about desertification, which is the process where fertile land turns into desert-like conditions. After introducing the issue, the lecturer explains that overgrazing and deforestation strip away vegetation. The first case shows land degradation because of soil erosion and nutrient loss. He goes on to say that another cause is climate change. For instance, drought intensifies desertification because of reduced rainfall and rising temperatures. In fact, this process threatens food security and water supplies in many regions. The professor emphasizes that sustainable farming and water conservation are solutions to slow the trend. So after hearing this lecture, I now have a better understanding of desertification and its consequences.
27. El Niño & La Niña
The professor goes into a ton of detail about El Niño and La Niña, which are climate patterns linked to Pacific Ocean temperatures. After introducing the concept, the lecturer explains that El Niño occurs when warm water spreads eastward, altering global weather. The first case shows unusual rainfall because of ocean warming and atmospheric shifts. She goes on to say that another pattern is La Niña. For instance, it brings cooler waters and stronger storms because of ocean cooling and pressure changes. In fact, both events affect agriculture, fisheries, and disaster risks worldwide. The professor highlights that scientists monitor these cycles for early warnings. So after hearing this lecture, I now have a better understanding of El Niño and La Niña.
28. Ocean Currents and Climate
The professor goes into a ton of detail about ocean currents, which are large-scale water movements that regulate climate. After introducing the idea, the lecturer explains that currents distribute heat around the globe. The first case shows climate influence because of warm streams and cold upwelling. He goes on to say that another example is the Gulf Stream. For instance, it keeps Europe’s winters milder because of heat transport and circulation. In fact, disruptions in currents could trigger extreme weather and rising seas. The professor emphasizes that understanding ocean circulation is vital for predicting climate change. So after hearing this lecture, I now have a better understanding of how ocean currents shape climate.
29. Water Pollution
The professor goes into a ton of detail about water pollution, which is the contamination of rivers, lakes, and oceans. After introducing the topic, the lecturer explains that industrial waste and agricultural runoff are major sources. The first case shows harm because of toxic chemicals and excess nutrients. She goes on to say that another problem is plastic pollution. For instance, marine animals die because of ingestion and entanglement. In fact, polluted water also threatens human health through diseases and unsafe drinking supplies. The professor emphasizes that stricter regulations and conservation efforts are necessary. So after hearing this lecture, I now have a better understanding of water pollution and its dangers.
30. Air Pollution Impacts
The professor goes into a ton of detail about air pollution, which is the release of harmful particles and gases into the atmosphere. After introducing the issue, the lecturer explains that vehicle exhaust and factory emissions are major contributors. The first case shows health problems because of respiratory illness and asthma. He goes on to say that another consequence is environmental damage. For instance, smog and acid rain occur because of chemical reactions and pollutants. In fact, air pollution also worsens climate change by adding greenhouse gases. The professor emphasizes that clean energy and public transportation are key solutions. So after hearing this lecture, I now have a better understanding of air pollution and its impacts.
🔹 Earth Science & Astronomy
31. Plate Tectonics
The professor goes into a ton of detail about plate tectonics, which is the theory that Earth’s crust is divided into moving plates. After introducing the concept, the lecturer explains that continents drift because of convection currents in the mantle. The first case shows geological change because of collisions and subduction zones. She goes on to say that another result is earthquakes and volcanoes. For instance, the Pacific Ring of Fire is active because of plate boundaries and friction. In fact, plate tectonics explains mountain building and ocean formation. So after hearing this lecture, I now have a better understanding of how plate tectonics shapes Earth.
32. Volcano Formation
The professor goes into a ton of detail about volcano formation, which occurs when magma reaches the surface. After introducing the process, the lecturer explains that tectonic activity creates openings in Earth’s crust. The first case shows eruptions because of pressure buildup and magma chambers. He goes on to say that another type is hotspot volcanism. For instance, the Hawaiian Islands formed because of mantle plumes and lava flow. In fact, volcanoes create fertile soils and new land, despite being dangerous. The professor emphasizes that studying eruptions helps scientists predict hazards. So after hearing this lecture, I now have a better understanding of volcano formation.
33. Earthquake Causes
The professor goes into a ton of detail about earthquakes, which are sudden shakes of Earth’s crust. After introducing the idea, the lecturer explains that they happen when stress builds up along faults and is suddenly released. The first case shows destruction because of seismic waves and ground displacement. She goes on to say that another cause is subduction zones. For instance, quakes near Japan occur because of colliding plates and ocean trenches. In fact, earthquakes can trigger tsunamis, landslides, and infrastructure damage. The professor emphasizes that seismic monitoring is crucial for safety. So after hearing this lecture, I now have a better understanding of what causes earthquakes.
34. Rock Cycle
The professor goes into a ton of detail about the rock cycle, which is the process by which rocks change form over time. After introducing the concept, the lecturer explains that igneous, sedimentary, and metamorphic rocks transform under heat, pressure, and erosion. The first case shows recycling because of weathering and sediment deposition. He goes on to say that another example is metamorphism. For instance, shale turns into slate because of compression and temperature changes. In fact, the rock cycle demonstrates Earth’s constant renewal of materials. The professor emphasizes that this cycle connects geological processes across time. So after hearing this lecture, I now have a better understanding of the rock cycle.
35. Weathering vs. Erosion
The professor goes into a ton of detail about weathering and erosion, which are processes that break down and move rocks. After introducing the idea, the lecturer explains that weathering occurs in place, caused by wind, water, or chemicals. The first case shows breakdown because of temperature changes and biological activity. She goes on to say that erosion involves transportation. For instance, rivers carry sediments downstream because of flowing water and gravity. In fact, both processes shape landscapes over millions of years. The professor emphasizes that understanding them explains valleys, mountains, and soil formation. So after hearing this lecture, I now have a better understanding of weathering and erosion.
36. Ice Ages and Glaciation
The professor goes into a ton of detail about ice ages, which are long periods when glaciers expand across continents. After introducing the topic, the lecturer explains that changes in Earth’s orbit and tilt contribute to cooling cycles. The first case shows land coverage because of advancing ice and lower temperatures. He goes on to say that another impact is glaciation. For instance, valleys and lakes were carved by glaciers because of erosion and deposition. In fact, ice ages reshaped entire ecosystems and influenced human migration. The professor emphasizes that studying past glaciation helps scientists predict climate change. So after hearing this lecture, I now have a better understanding of ice ages and glaciation.
37. Seasons and Earth’s Tilt
The professor goes into a ton of detail about seasons, which are caused by Earth’s tilt on its axis. After introducing the concept, the lecturer explains that as Earth orbits the sun, different hemispheres receive varying amounts of sunlight. The first case shows summer and winter because of tilt angle and solar intensity. She goes on to say that another effect is day length. For instance, longer summer days occur because of Earth’s position and sun exposure. In fact, the professor highlights that without the tilt, Earth would have little seasonal variation. So after hearing this lecture, I now have a better understanding of how Earth’s tilt creates seasons.
38. Gravity and Planetary Motion
The professor goes into a ton of detail about gravity, which is the force that pulls objects toward each other. After introducing the idea, the lecturer explains that Newton described planetary orbits using gravitational attraction. The first case shows stable motion because of force balance and inertia. He goes on to say that another example is tides. For instance, the moon pulls Earth’s oceans because of gravitational interaction and orbital cycles. In fact, gravity also shapes galaxies and black holes. The professor emphasizes that gravity is universal and governs cosmic structure. So after hearing this lecture, I now have a better understanding of gravity and planetary motion.
39. Life Cycle of Stars
The professor goes into a ton of detail about the life cycle of stars, which describes how stars form, evolve, and die. After introducing the process, the lecturer explains that stars begin as clouds of gas that collapse under gravity. The first case shows growth because of nuclear fusion and energy release. She goes on to say that another stage is death. For instance, massive stars explode as supernovae because of fuel depletion and core collapse. In fact, star life cycles create heavy elements essential for planets and life. The professor emphasizes that stellar evolution is key to understanding the universe. So after hearing this lecture, I now have a better understanding of the life cycle of stars.
40. Big Bang Theory
The professor goes into a ton of detail about the Big Bang theory, which is the scientific explanation for the origin of the universe. After introducing the concept, the lecturer explains that about 13.8 billion years ago, the universe began from a hot, dense state and expanded rapidly. The first case shows evidence because of cosmic microwave background and galaxy expansion. He goes on to say that another proof is light element abundance. For instance, hydrogen and helium dominate because of early nuclear reactions and cosmic cooling. In fact, the professor emphasizes that while details are still debated, the Big Bang remains the most accepted model. So after hearing this lecture, I now have a better understanding of the Big Bang theory.