酶的化学本质除有催化活性的______外都是______。

读“太阳照射地球示意图”，（图中阴影表示夜半球），回答：

小题1:图示时间为(    )。

A．3月21日

B．6月22日

C．9月23日

D．12月22日小题2:此时B点以北会出现(　　)现象。

A．太阳直射

B．极夜

C．极昼

D．无法判断

商业银行因吊销许可证被撤销的，哪一单位应当依法及时组织清算组，进行清算，按照清偿计划及时偿还存款本金和利息等债务( )。

A．该商业银行住所地的中级人民法院

B．中国人民银行

C．中国银行业监督管理委员会

D．该商业银行住所地的市级工商局

What is time? Is it a thing to be saved or spent or wasted, like money? Or is it something we have no control over, like the weather? Is it the same all over the world? That’s an easy question, you say. Wherever you go, a minute is 60 seconds, an hour is 60 minutes, a day is 24 hours, and so forth. Well, maybe. But in America, time is more than that. Americans see time as a valuable resource. Maybe that’s why they are fond of the expression, “Time is money.”

Because Americans believe time is a limited resource, they try to keep and manage it. People in the US often attend conferences or read books on time management. It seems they all want to organize their time better. Professionals carry around pocket planners(计划书) — some in electronic form — to keep track of appointments and deadlines. People do all they can to press more life out of their time.

To Americans, punctuality is a way of showing respect for other people’s time. Being more than 10 minutes late to an appointment usually calls for an apology, and maybe an explanation. People who are running late often call ahead to let others know of the delay. Of course, the less formal the situation, the less important it is to be exactly on time. At informal get-togethers, for example, people often arrive as much as 30 minutes past the appointed time. But they usually don’t try that at work.

American lifestyles show how much people respect the time of others. When people plan an event, they often set time days or weeks in advance. Once the time is fixed, it takes almost an emergency to change it. If people want to come to your house for a friendly visit, they will usually call first to make sure it is convenient. Only very close friends will just “drop by” unannounced. Also, people hesitate to call others late at night for fear they might be in bed. The time may vary, but most folks think twice about calling after 10:00 pm.

Even Americans would admit that no one can master time. Time, like money, slips all too easily through our finger. And time, like the weather, is very hard to predict. However, time is one of life’s most precious gifts.

小题1:The main idea of the passage is _______.

A．time is money

B．different attitude toward time in the world

C．how to save time

D．how Americans treat time小题2:In the fourth paragraph, the writer mainly tells us that _________.

A．Americans respect others’ time in daily life

B．Americans seldom call after 10:00

C．Americans inform before paying a visit to their friends

D．when planning an event, Americans usually fix time ahead of time小题3:The underlined phrase “think twice” (in Paragraph 4) probably means “_______ “.

A．think for a second time

B．be careful

C．be afraid

D．pay attention小题4:It can be inferred from the passage that ________.

A．Americans like time better than anything else

B．generally speaking, Americans respect their time

C．on the whole, Americans treasure their time

D．Americans consider their time is difficult to master and predict

近年来马克思的《资本论》在西方一些国家销量大增。列宁曾说，马克思的《资本论》的成就之所以如此之大，是由于这本书使读者看到整个资本主义社会形态是个活生生的形态，既有骨骼，又有血肉。人类社会作为一种活的有机体，其骨骼系统是指（ ）。

A．地理环境、人口因素和生产方式等社会物质生活条件

B．与一定的生产力相适应的生产关系

C．建立在一定经济基础之上的政治法律制度及设施

D．由政治法律思想、道德、宗教、哲学等构成的社会意识形态

简述电网由哪几部分组成？