[单项选择]A hundred (41) years ago there were a lot of dinosaurs (恐龙) in the world. Some lived on land. Some lived in the sea. Some (42) fly. A lot of them (43) very large and some had horns (角) or long teeth (44) the monsters (怪物) in films. Most of the dinosaurs were plant-eaters, but some of them could kill (45) eat very big animals.
The world was full of dinosaurs for 135 million (百万，百万个) years. 60 million years ago, however (然而，不管怎样), they were (46) dead. (47) happened to them
Some scientists say that about 65 million years ago the world’s climate (气候) (48) cold (寒冷的，伤风) and this cold climate killed the dinosaurs.
Now we eau only see dinosaur bones (骨骼) in (49) , but we can not see a (50) dinosaur any more.


A. all
B. not
C. both