A、Because they have all been shot. B、Because they are too dangerous. C、Because they are all hiding under the rivers. D、Because t

Crocodiles only live where it is hot. They are found in India, Australia, Africa and America. They. spend most of their time lying around in the mud or the rivers. The crocodile’s long powerful tail is used when the animal is swimming. It is also an excellent weapon, because it call be swung with great speed and force. One blow will knock down a man or even a big animal at once. The crocodile is very well protected against its enemies by the hard bony plates which cover most of its body, (30)but because of the way its neck is formed, it cannot turn its head from side to side and so it can only see in front of itself. The crocodile has its teeth cleaned by the crocodile bird.
For its food this bird takes the bits left in the crocodile’s mouth. This helps the crocodile, which cannot clean its own teeth, for it cannot move its tongue up and down. (31)With its rows of terrible pointed teeth it seizes its food, which may be a fish, an animal, or even a careless man, and then holds ii below the water until it drowns.
     The long-nosed crocodile is shy and timid and because of this, the people of West Africa where it lives, sometimes catch it for food. Many, many centuries ago there were crocodiles in England. We know this because we have found their bones buried far down in the earth on which London is built. (32)But the Britain of today is too cold for them to live in. This is a good thing for English people for crocodiles may grow to over thirty feet in length. When they lie floating in the water, they look like floating tree-trunks and it is often impossible to tell that they are there.