PH3一种无色剧毒气体，其分子结构和NH3相似，但P-H键键能比N-H键键能低。

It’s in the 2010s.You feel sick, so you go to the doctor. She checks your fever, looks at your throat, and asks what you’ve been thinking about lately. When you leave, she gives you some medicine, but also a list of thinking skills that you are supposed to practice daily. She says that the way you think is causing some of your illness.

Doctors and other scientists who study the human mind and try to explain why people act in the way that they do, called psychologists (心理学家), are starting to believe it. You know that your brain (脑) is connected to every part of your body through your nervous system (神经系统). Now scientists have proved that how you think and feel can have an influence on the health of your body.

Stress is caused whenever there is a problem or a change in your life. Of course, everybody has stress more or less; nobody’s life is perfect. In fact, stress is necessary. Without stress, we would never learn anything or grow or change. We would probably be bored to death. But too much stress can hurt you. It can weaken your body’s protection so that you are more likely to catch diseases. It can even make you more likely to have an accident.

When you feel stressed, your brain sends a message to your body to produce a chemical called adrenaline (肾上腺素). Adrenaline speeds up your breathing and your heartbeat. Today you have a different kind of stress. Problems like endless homework or troubles with your family are the kind of things you can’t fight or run away from, so you don’t use up all that adrenaline. It just stays bottled up inside you, and that’s what can do something bad to you.

What can you do about stress? First, you can try to find ways to change things so you aren’t under so much stress. You can set up a plan to finish homework or go to a doctor or a psychologist to try to work things out with your family or your friends. But sometimes you can’t change a stressful situation. Sometimes you don’t even want to. A big change might be a good change, but it will still be stressful.

The link (关联) between your body and brain works in two ways. Your body can help your mind deal with stress. If you are under stress, you need to take especially good care of your body. It’s important to get enough sleep and eat nutritious (有营养的) meals. Some people take a vitamin-mineral pill every day. Another thing that you can do is daily exercise. If you go walking or do aerobic dancing or work out at the gym (体育馆), you give your body a chance to burn up some of that adrenaline. Of course, a person who isn’t used to much physical activity should start slowly. Anyone with a continuing physical problem should check with a doctor before starting any exercise programs.

小题1:Which of the following is TRUE according to the passage?

A．You shouldn’t go to the gym if you are under stress.

B．One can do his homework to burn up adrenaline.

C．Disease and accidents are caused by stress.

D．Everyone needs stress to improve himself.小题2:From the last sentence of Paragraph 5 we can infer (推断) that _____________.

A．it’s difficult to change a stressful situation

B．it’s not stressful when a good change takes place

C．a big change will cause another stressful situation

D．a stressful situation can’t be changed without any effort小题3:What is probably the best title for this passage?

A．The Body-Brain Link

B．The Causes of Stress

C．The Advice on Health

D．The Nervous System

在基托的制作过程中，操作不当，会导致基托中产生气泡或基托变形。

热凝塑料基托发生变形的原因是（）

A.压力太小

B.升温过低

C.升温过慢

D.填胶过早

E.冷却太快，开盒太早

因素A、B、C均可独立的引起某病而无须其他两种因素存在，但都必须是在因素X存在的前提下。因素X单独存在不会引起该病。因素A是（）。

A.必要且充分条件

B.必要条件，但不是充分条件

C.充分条件，但不是必要条件

D.既不是必要条件，也不是充分条件

E.以上都不对

成年男性与女性颈部外形较明显的区别是（）。

A.男性静坐时颈部血管可显露

B.男性颈部较细长

C.男性甲状软骨较突出

D.男性转头时可见胸锁乳突肌突出

E.男性颈部直立，两侧对称