题目内容
I. Read the passage and complete the mind map.
Sharks are actually fish!Some pups (鲨鱼幼崽) grow inside their mothers like human babies do,but most hatch from eggs.
Unlike most fish,sharks do not have bones? but they do have lots of other similarities to bony fish. They are cold-blooded and breathe through gills (鳃) . And sharks have several rows of sharp-pointed teeth and powerful jaws to tear off big pieces of food. They eat bony 
fish,sea.turtles and other sea animals. They have an excellent sense of smelling? which helps them find food. Many sharks eat near the surface of the water,but will also dive down deeper to look for food.
Not all sharks are large. Some only grow up to 7 inches long. However,most kinds of sharks grow to about 5-7 feet long,which is about the same height as an average adult. Not all sharks are dangerous to humans,either. There are over 350 kinds of
sharks,but only about 25 of those.have ever been known to attack humans.
bony fish,
some most
no bones.
some pups grow inside their mothers, most
food: sea turtles,other sea animals
size: grow up to 7 inches long,grow to about 5-7 feet long
appearance: several rows of sharp-pointed teeth,powerful jaws
characteristics: pups hatch from eggs,cold-blooded,breathe through gills,an excellent sense of smelling
