[单项选择]When the weather is hot, you go to a lake or an ocean. When you are near a lake or an ocean, you feel cool .Why The sun makes the earth hot, but it cannot make the water very hot. Although the air over the earth becomes hot, the air over the water stays cool. The hot air over the earth rises. Then the cool air over the water moves in and takes the place of the hot air. When you are near a lake or an ocean, you feel the cool air when it moves in. You feel the wind. And the wind makes you cool.
Of course, scientists cannot answer all of your questions. If we ask, "why is the ocean full of salt" Scientists will say that the salt comes from rocks. When a rock gets very hot or very cold, it cracks. Rain falls into the cracks. The rain then carries the salt into the earth and then into the rivers. The rivers carry the salt into the ocean. But then we ask, "what happens to the salt in the ocean The ocean does not get more salty every year." Scientists are not sure about the answer to thi
A. the water is cold
B. the earth is hot
C. the water is colder that the earth
D. the cool air from the water moves towards the land

[单项选择]When the weather is hot, you go to a lake or an ocean. When you are near a lake or an ocean, you feel cool .Why The sun makes the earth hot, but it cannot make the water very hot. Although the air over the earth becomes hot, the air over the water stays cool. The hot air over the earth rises. Then the cool air over the water moves in and takes the place of the hot air. When you are near a lake or an ocean, you feel the cool air when it moves in. You feel the wind. And the wind makes you cool.
Of course, scientists cannot answer all of your questions. If we ask, "why is the ocean full of salt" Scientists will say that the salt comes from rocks. When a rock gets very hot or very cold, it cracks. Rain falls into the cracks. The rain then carries the salt into the earth and then into the rivers. The rivers carry the salt into the ocean. But then we ask, "what happens to the salt in the ocean The ocean does not get more salty every year." Scientists are not sure about the answer to thi
A. people feel cool when they are near a lake or an ocean
B. scientists can explain everything we want to know
C. scientists can explain many things but not everything
D. the salt in the ocean comes from rocks

[单项选择]

Weather changes when the temperature and the amount of water in the atmosphere change. We can see and feel water coming from the atmosphere when we have rain. But the water must somehow get back to the atmosphere. Meteorologists call this the water cycle.
There are many stages in the water cycle. Rain falls when water vapor in clouds condenses (凝结). Drops of water form and fall to the ground. The water soaks into the ground and feeds streams and rivers. A lot of rain falls into the sea. The heat of the sun evaporates some of the water in the ground and in the rivers, lakes, and the sea. It changes the liquid water into water vapor. The vapor rises onto the air. Water vapor is normally invisible. On a very damp of humid day, however, you can sometimes see water vapor rising from a puddle (水坑) or pond in a mist (薄雾) above the water. Water vapor also gets into the air from living things. Trees and other plants take in water through their roots and give off water vapor from t
A. Water cycle.
B. Water vapor.
C. How rain forms
D. Water, vapor, rain.