如果在施工承包合同执行中，发生了合法的工程变更，确定变更后工程款的办法是( )。A

阵发性房性心动过速的心电图表现为()

A.QRS<0.12s

B.可见心室夺获

C.QRS>0.12s

D.心房率150～250／min

E.P′波与窦性者不同，可直立或倒置

淋巴造血组织肿瘤可见“星空”现象的有（）。

A.淋巴母细胞性淋巴瘤

B.粒细胞肉瘤

C.弥漫大B细胞淋巴瘤

D.Burkitt淋巴瘤

E.滤泡树突状细胞肉瘤

Common sense would tell us that physically active children may be more likely to become active and healthy adults.

In the United States, elementary and middle schools are advised to give students two and a half hours of physical activity a week. That is what the Centers for Disease Control and Prevention and the American Heart Association recommend. They say high schools should provide about four hours of physical activity each week.

Yet many schools across the country have reduced their physical education programs. Just this week, a study reported that life expectancy has fallen or is no longer increasing in some parts of the United States. The situation is worst among poor people in the southern states, and especially women. Public health researchers say it is largely the result of increases in fatness, smoking and high blood pressure. They also blame differences in health services around the country.

In 2006, a study found that only four percent of primary schools provided daily physical education all year for all grades. This was true of eight percent of middle schools and two percent of high schools. The study also found that twenty-two percent of all schools did not require students to take any P.E.

Charlene Burgeson , a health expert says one problem for P.E. teachers is that schools are under pressure to put more time into academic subjects. Also, parents may agree that children need exercise in school. Yet many parents today still have bad memories of being chosen last for teams because teachers favored the good athletes in class.

But experts say P.E. classes have changed. They say the goal has moved away from competition and toward personal performance, as a way to build a lifetime of activity. These days, teachers often lead activities like weight training and yoga.

Some parents like the idea of avoiding competitive sports in P.E. class. Yet others surely dislike that idea. In the end, schools may find themselves in a no-win situation.

小题1: The underlined word “expectancy” in Paragraph 3 probably means “       ”                            

A．quality

B．length

C．exception

D．depth小题2:According to the passage which of the following may not lead to poor health?

A．Fatness.

B．Smoking

C．High blood pressure.

D．Health service小题3: What can be inferred after you read this passage?

A．Physical activities are becoming more and more popular in American schools.

B．All the schools provided daily physical education all year for all students.

C．Parents think children need physical education for their bad memories.

D．Students spent less time on physical education for academic pressure.小题4: What is the main idea about this passage?

A．P.E. is the most important subject for all students.

B．P.E has changed its goal for some reasons in America.

C．It introduces us the present situation of P.E in American schools and its cause.

D．P.E can help students improve their academic subjects.

某建筑公司(乙方)于2007年4月20日与某厂(甲方)签订了修建建筑面积为3000m²工业厂家(带地下室)的施工合同。乙方编制的施工方案和进度计划已获监理工程师批准。该工程的基坑开挖土方量为4500m³，假设直接费单价为4.2元/m²，综合费率为直接费的20%。该基坑施工方案规定：土方工程采用租赁一台斗容量为1m³的反铲挖掘机施工(租赁费450元/台班)。甲、乙双方合同约定2007年5月11日开工，2007年5月20日完工。在实际施工中发生了如下几项事件。
事件1：因租赁的挖掘机大修，晚开工2d，造成人工窝工10个工日。
事件2：施工过程中，因遇软土层，接到监理工程师2007年5月15日停工的指令，进行地质复查，配合用工15个工日。
事件3：2007年5月19日接到监理工程师于2007年5月20日复工令，同时提出基坑开挖深度加深2m的设计变更通知单，由此增加土方开挖量900m³。
事件4：2007年5月20～5月22日，因下大雨迫使基坑开挖暂停，造成人工窝工10个工日。
事件5：2007年5月23日用30个工日修复冲坏的永久道路，2007年5月24日恢复挖掘工作，最终基坑于2007年5月30日挖坑完毕。
问题

关于三羧酸循环过程的叙述正确的是（）。

A．循环一周生成4对NADH

B．循环一周可生成2ATP

C．乙酰CoA经三羧酸循环转变成草酰乙酸

D．循环过程中消耗氧分子

E．循环一周生成2分子C0₂