心肌兴奋性变化的特点是（）。 A.绝对不应期短 B.有效不应期特别长 C.相对不应期

同温同压下两个容积相等的贮气瓶，一个装有C₂H₄气体 ，另一个是装有C₂H₂气体和C₂H₆气体的混合气体，则两瓶内的气体一定具有相同的[ ]

A．质量

B．原子总数

C．碳原子数

D．密度

第二产程出现的标志是

A．外阴膨隆

B．胎头拨露

C．胎头着冠

D．肛门括约肌松弛

E．宫口开大10cm

无氨蒸馏水的制备方法是（）

A.将蒸馏水加硫酸和高锰酸钾后再蒸馏

B.将蒸馏水用全玻璃皿重蒸馏

C.于水中加NaOH到pH>12后再蒸馏

D.于水中加NaOH和AlCl₃后进行蒸馏

E.于水中加CaCl₂后再蒸馏

If you want to keep healthy, you should have good habits. What is a habit? It is something we do very often. We don’t even think when we do it. It has become a part of our lives.

“Early to bed, early to rise makes a man healthy, wealthy and wise.” This is an old English saying. Do you know what it means? It means that we must go to bed early at night and get up early in the morning. If we do, we shall be healthy, rich and clever.

Is this true? Perhaps it is. We know the body must have enough sleep. Boys and girls need eight or nine hours’ sleep every day.

Some people go to bed late at night and get up late in the morning. This is a very bad habit. Then you will not think or do your work well. Of course, you can’t be healthy, wealthy or wise.

When we get up early in the morning, we can go out and do morning exercises. Exercise means doing things with the body. Walking, running jumping, swimming, and playing ball games are all exercise. If we don’t exercise, our body will become weak.

Exercise helps the blood (血液) to move around inside our body. Blood takes food to all parts of our body.

Our body also needs air to breathe. Without air, we will die. We must have lots of clean fresh air if we want to be healthy. That is why many people like to go out to do morning exercise.

1 From the passage we know that it is good for our health to ____ .

A. eat a lot         B. go to bed early   C. get up late      D. go to bed late

2 How long should young boys and girls need to sleep a day?

A. More than ten hours                B. Over eleven hours.

C. Less than seven hours.             D. Eight hours or so.

3 If we want to keep healthy, we must ____ .

A. eat more food                         B. sleep more     C. get up late D. take enough exercise

4 Which of the following habits is NOT GOOD?

A. Don’t go to bed until twelve o’clock..

B. Take a walk after supper.

C. Run in the open air early in the morning.

D. Climb hills for half an hour early in the morning.

5 Which sport is NOT mentioned in the passage?

A. Jumping.       B. Swimming.    C. Riding.          D. Running.

患者自进食海鲜后，次日出现剧烈水样腹泻，无腹痛及里急后重。为确诊应做的检查是

A．血常规
B．粪便常规
C．粪便常规及悬滴检查
D．粪便常规及痢疾杆菌培养
E．粪便隐血试验