a=(m，1)，b=(1-n，1)（其中m、n为正数），若a∥b，则1m+2n的

下列加点成语使用恰当的一项是（   ）

A．电视画面显示，当日的民主党竞选总部沸反盈天，奥巴马的支持者们有序地握手拥抱，庆祝奥巴马开创新的选举记录，成为美国历史上第一位黑人总统。

B．那张记忆中的容颜，如此美轮美奂，宿命中的故事不该曲终人散。

C．白居易提出“文章合为时而著，歌诗合为事而作”的口号，认为写文章要有自己的见解，表达自己的真情实感，切不可拾人牙慧。

D．国学大师陈寅恪先生在晚年因为眼疾，只能述而不作，由他的助手记录下他口述的内容，最终完成了学术专著《柳如是别传》的创作。

乐乐学习很刻苦，成绩也非常好，就是对班集体不大关心，集体的活动也不参加。他认为学习好坏是靠个人努力的，集体是靠不住的。这种说法[ ]

A、是错误的，因为个人和集体是不可分割的，个人在集体中成长    

B、是错误的，因为离开集体，个人就无法长大  

C、是正确的，因为个人与集体没多大的关系     

D、是正确的，因为个人学习、生活可以离开集体

The effects of rapid travel on the body are actually far more disturbing than we realize. Jet Lag is not a psychological consequence of having to readjust to a different time zone. It is due to changes in the body’s physiological regulatory mechanisms, specifically the hormonal systems, in a different environment.

Now that we understand what Jet Lag is, we can go some way to overcome it. A great number of the body’s events are scheduled to occur at a certain time of day. Naturally these have to be regulated, and there are two regulatory systems which interact.

One timing system comes from the evidence of our senses and stomachs, and the periodicity we experience when living in a particular time zone. The other belongs in our internal clocks (the major one of which may be physically located in a part of the brain called the suprachiasmatic nucleus) which, left alone, would tie the body to a 25-hour rhythm. Normally the two timers are in step, and the surroundings tend to regularize the internal clocks to the more convenient 24-hour period.

  If, however, you move the whole body to a time zone which is four hours different, the two clocks will be out of step, like two alarm clocks which are normally set together, but which have been reset a few hours apart. Whereas the two clocks would normally sound their alarms together, now they ring at different times. Similarly, the body can be set for evening while the sun is rising.

In time the physiological system will reset itself, but it does take time. One easily monitored rhythm is palm sweating. A man flown to a time zone different by 10 hours will take eight days to readjust his palm sweat. Blood pressure, which is also rhythmical, takes four days to readjust.

What can we do about it? It is not feasible to wait four days until the body is used to the new time zone. Fortunately there is a short cut. It relies on two things-the power of the stomach to regulate the timing of other events, and the pharmacological actions of coffee. The basic assumptions are:

Coffee delays the body clock in the morning, and advances it at night. Coffee at mid-afternoon is neutral. Protein in meals stimulates wakefulness, while carbohydrates promote sleep. Putting food into an empty stomach helps synchronize the body clock.

46. What is jet lag associated with?

A. Psychological change.           B. Physiological change.

C. Inexperience of rapid travel.      D. Unfamiliar environment.

47. What helps us to adjust to a 24-hour rhythm?

A. Alarm clock.                  B. Suprachiasmatic nucleus in our brain.

C. Signals from outside of the body.   D. Our senses and stomachs.

48. What do we know from the fifth paragraph?

A. A person moving to a different time zone will suffer from high blood pressure.

B. A person moving to a different time zone will sweat a lot.

C. Moving to a different time zone will affect both palm sweat and blood pressure.

D. If the rhythm of blood pressure and palm sweat are not in step, there will be jet lag.

49. What should we do if we want to stay awake?

A. To take coffee at three o’clock in the afternoon.

B. To have meals that contain lots of protein.

C. To have some carbohydrate drinks.

D. To stop putting food into our stomach.

50. How can we cure jet lag?

A. To sleep for days.      B. To wait for self-recovery.

C. To drink tea.          D. To get something to eat.

影响纤维吸湿的外界因素主要有哪些？

下列关于急腹症手术适应证的叙述中，最合适的一项是（）

A.粘连性肠梗阻不需手术治疗

B.先有发热的急性腹痛，一般是外科急腹症，均应考虑手术

C.急性胰腺炎，血淀粉酶不高者不考虑手术

D.消化道穿孔不是剖腹手术的绝对适应证