1. (2021九上·深圳开学考) 阅读短文，回答问题

From goldfish to sharks, fish of all sizes have lived on Earth for hundreds of millions of years. But do they ever get thirsty?

The answer is yes! Some fish do, at least. But there is a big difference between fish that live in saltwater and ones that live in freshwater.

Bony fish have some salt concentration（含盐量）  in their bodies. For bony fish in saltwater, their concentration is lower than the water they live in. Through osmosis （渗透作用）, they drink lots of water, so it's easy to say that they can be thirsty. Drinking saltwater is never a good idea for humans（鳃）.

However, sharks are an exception. Sharks can make their salt concentration match the water around them. They do this by building up urea  （尿素）  in their blood

Freshwater fish, on the other hand, are unlikely to become thirsty. Because they live in a less salty environment（冲淡） their blood. Freshwater fish therefore need to get rid of this extra water. So now we know that saltwater fish can become thirsty and drink water, while freshwater fish will avoid drinking but pee （小便）

1. （1） What's the main idea of this story?

   A . Fish have a long history of living on Earth. B . Fish of all sizes can become thirsty like humans. C . Fish drink saltwater when they get thirsty. D . Fish are different in terms of whether they get thirsty.
3. （2） Why do bony fish drink lots of water?

   A . Because they have a high salt concentration. B . Because they need to take in salt through their grills. C . Because they will lose lots of water through their bodies. D . Because they become thirsty more easily than humans.
5. （3） Why are Sharks mentioned in the fourth paragraph?

   A . To prove that they are the most unusual creatures in the sea. B . To prove that freshwater is not good for them to live in. C . To prove that not all saltwater fish drink lots of water. D . To prove that they are dangerous because they may explode.
7. （4） Which of the following statements is TRUE about freshwater fish?

   A . They don't get thirsty at all because they live in saltwater. B . Too much water in their blood can be bad. C . They get thirsty and drink water just like saltwater fish. D . They pee a lot after drinking too much water.
9. （5） Where can you find this story in?

   A . a fashion magazine B . a travel guide C . a science book D . a storybook