主变压器开关停电时，应先停电源侧，再停负荷侧。（）

通常所有车轮的外倾角都相等。各轮外倾角大小不等会引起（）以及汽车向（）的一侧转向。

C

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 litres of water every day, but we need not drink this amount 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. Cold water!

64．Do most people drink five litres of water every day?

A. Yes, because water is the most important

B. No, because what we eat contains water

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

D. No, because we are not thirsty

65．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.

66．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.

67．Which of the following is not right?

A. Cold water is the best drink.

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

C. Not all the people realize water is the most important.

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

管路直径d=1000mm，若输送运动黏度v=1.14cm²/s的石油，临界雷诺数为2300，则保持层流流态的最大流量约为（）m³/h。

A．341

B．541

C．741

D．941

退税

实现法治国家的一个基本前提是（）。

A、具备高度的民主政治

B、具备完备的制度体系

C、具备高素质的法官队伍

D、具备强有的力的执法力量