There are two species of crocodile in Australia—the saltwater crocodiles and the freshwater ones.
Saltwater crocodiles are among the world's largest crocodiles, with males often reaching five metres. But some can reach six to eight metres. Females grow up to 2.5 metres long.
Saltwater crocodiles live in rivers, and coastal waters in northern Australia and eat a wide variety of prey. The young ones stick to insects, small reptiles and fish. But adults hunt for bigger prey like snakes, monkeys and cattle. And they have been known to attack humans.
Freshwater crocodiles, however, aren't usually dangerous to people. They live in freshwater streams, rivers and large water holes in northern Australia. Freshwater crocodiles aren't as big as saltwater ones either, reaching a length of three metres at most.
Crocodiles first appeared 200 million years ago and lived originally on land. But they soon evolved into aquatic (水生的) animals.
These reptiles are excellent predators (肉食动物) and have few natural enemies. Crocodiles have about 30 or 40 teeth in each jaw. And it is the jaw that gives a unique feature to them.
A crocodile can close its jaws with such force that it can break the bones of some animals. Yet, once the jaws are shut, they're so weak that they can be held together by a person's hand.
To reproduce, crocodiles, like other reptiles, lay eggs. One female can produce between 20 and 90 eggs at a time. Once laid, female crocodiles bury their eggs in sand or mud, where they are left to hatch. Some females stay in the area to protect the nest and look after the young after they hatch, but often other predators eat the eggs.
11. The largest crocodiles in Australia can reash a length of ________.
A.three metres | B.five metres |
C.eight metres | D.ten metres |
12. The following features of saltwater crocodiles and freshwater crocodiles have been mentioned in the passage except ________.
A.their eating habits |
B.the law to find a mate |
C.the key to their strong power |
D.threat against their reproduction |
13. What do saltwater crocodiles and freshwater crocodiles have in common?
A.Theh have the same size. |
B.They both live in freshwater streams. |
C.They are usually both dangerous to people. |
D.They both live in northern Australia. |
14. We can infer from Paragraph 7 that ________.
A.crocodiles close their jaws very quickly |
B.crocodiles' jaws are easy to control when they are open |
C.crocodiles are not dangerous to people when their jaws are closed |
D.crocodiles' jaws are very powerful when closing |
15. What usually happens after crocodile eggs are laid?
A.The eggs will be kept under the ground. |
B.The eggs will be hatched by their parents. |
C.The male crocodiles will protect the eggs. |
D.The female crocodiles will leave the nest. |