简述自卸汽车货箱的举倾机构由哪些主要总成组成及工作原理。

Passage OneA recent study indicates that the “short sleepers” had been more or less average in their sleep needs until the men were in their teens. But at about age 15 or so, the men voluntarily began cutting down their nightly sleep time because of pressures from school, work, and other activities. These men tended to view their nightly periods of unconsciousness as bothersome interruptions in their daily routines.In general, these “short sleepers” appeared ambitious, active, energetic, cheerful, conformist in their opinions, and very sure about their career choices. They often held several jobs at once, or work fullor parttime while going to school. And many of them had a p urge to appear “normal” or “acceptable” to their friends and associates.When asked to recall their dreams, the “short sleepers” did poorly. More than this, they seemed to prefer not remembering. In similar fashion, their usual way of dealing with psychological problems was to deny that the problem existed, and then to keep busy in the hope that the trouble would go away.The sleep patterns of the “short sleepers” were similar to, but less extreme than, sleep patterns shown by many mental patients categorized as manic.The “long sleepers” were quite different indeed. According to the study, these young men had lengthy sleeps since childhood. They seemed to enjoy their sleep, protected it, and were quite concerned when they were occasionally deprived of their desired 9 hours of nightly bed rest. They tended to recall their dreams much better than did the “short sleepers”.Many of the “long sleepers” were shy, anxious, introverted, inhibited, passive, mildly depressed, and unsure of themselves (particularly in social situations). Several openly state that sleep was an escape from their daily problems.

Many “short sleepers” are likely to hold the view that ().

A．sleep is a withdrawal from the reality

B．sleep interferes with their sound judgment

C．sleep is the least expensive item on their routine program

D．sleep is the best way to deal with psychological troubles

简述菌藻类食物的保健作用。

下面关于建筑工程合同的叙述正确的是（）

A.是诺成合同

B.是要物合同

C.是单务合同

D.对建筑施工企业而言是从合同

People have cooked over open fires and dirty stoves for all of human history, but the simple fact is they are slowly killing millions of people and polluting the environment. Engineers and development professionals have worked on this problem for decades. My own involvement stretches back many years, and I’m well aware that well-meaning efforts have been launched, but none have managed to match the scope of the challenge.

阴极电泳涂装时阳极区会产生有机酸进而腐蚀阳极，为除去有机酸可作如下处理方法：添加（）或采用（）。