Of all the things we eat and drink, water is the most important. Not all people realize this, but it is quite true. The human body can live without food for a long time, but two or three days without water usually result in death.
Many people do not understand how much water the human body needs, but many people do not drink enough, especially in the hot weather. Most people drink when they are thirsty but often need more water after exercises.
65 to 70 percent of the human body is water. Water is important in several different ways. Most people need five to seven liters（升） of water every day, but we needn’t drink this amount(量) because a lot comes from the food we have. If we don’t have enough water, however, we will feel tired and many become ill. Do you know what the best drink is? Yes, you are right. Cool water!
When do we need more water?________

A．In cold weather or after exercises.

B．In hot weather or after exercises.

C．Before breakfast, lunch and supper.

D．When we feel tired or become ill.

How much water are there in the human body?_________

A．About three fourths of the human body is water.

B．Nearly a half of the human body is water.

C．Less than a half of the human body is water.

D．Almost one fourth of the human body is water.

Must most people drink five liters（升）of water every day?_______

A．Yes, because water is the most important

B．No, because what we eat contains（包含）water

C．Yes, because we can’t live without water

D．No, because we are not thirsty

Which of the following is not right?_________

A．Cool water is the best drink.

B．Few people understand how much water the human body needs.

C．All the people don’t realize water is the most important.

D．When we feel tired or become ill, we never need any water.