阅读理解。 Millions of years ago there were many types of dinosaurs on earth. Most dinosaurs were plant-eaters. The Apatosaurus, for example, had a long thin neck so that it could eat leaves from trees. Other dinosaurs were meat-eaters. The Tyrannosaurus Rex killed smaller dinosaurs for food. Dinosaurs were real animals that once lived on the earth, but they died out about 65 million years ago. The disappearance of the dinosaurs is in some way a great mystery (谜). Some scientists think that the climate (气候) changed suddenly. Fossils (化石) of trees tell us that the temperature dropped a lot and that the level of the sea dropped as well. This means that it got suddenly much colder. Perhaps the dinosaurs were too slow to change with the climate. A new idea is that a meteor (流星) crashed into the earth. Scientists discovered a place in Mexico where they think the meteor crashed. They think that there was a lot of dust from the meteor. The dust landed on the plants.Also the dust blocked (阻挡) the sun's light for as long as five years. Many animals, including dinosaurs, were plant-eaters, and perhaps the dust killed them. This means there was nothing left for meat- eating dinosaurs to eat, and so they died out. But, as many animals from that time didn't die, we are not 100% sure what really happened. 1. What is the subject discussed in the text? [     ] A. Dinosaurs, the real animals living millions of years ago. B. The two types of dinosaurs. C. The probable reasons for dinosaurs disappearance. D. A meteor crashed into the earth. 2. What are the two possible explanations to the dinosaurs disappearance? [     ] A. Temperature dropping and sea level dropping. B. Climate changing and meteor's crashing. C. The dropping of temperature and sea level. D. Climate changing and the dust blocking the sun. 3. What is the direct cause of the disappearance of meat-eating dinosaurs? [     ] A. A meteor's crashing. B. The dust blocking the sun. C. The plant-eating dinosaurs death. D. It is still unknown.