生产建设项目水土保持工程规模根据以下（）内容分析确定。 A.水土流失防治标准 B.地

Researchers have announced（宣布）the result of two studies on the health effects of the drug aspirin（阿斯匹林）. One study shows aspirin can sharply reduce the chance that a healthy, older man will suffer from a heart attack（心脏病）.

　 The study offered two new results from earlier findings. It said taking one aspirin pill every other day helped only healthy men over the age of fifty. It also said aspirin gave the greatest protection against heart attacks to men with low blood cholesterol（胆固醇）levels.

　 Earlier in the United States began a major aspirin study in the early 1980s. It included 22,000 healthy men doctors. All were between the ages of fifty and eighty-four. Almost 11,000 of the doctors took a harmless（无害的）pill that contained no drug. The men did not know which kind of pill they were taking.

　 The doctors who took aspirin suffered 44% fewer heart attacks than those taking the harmless pill. 139 men who took aspirin suffered from heart attacks. Ten of them died. 239 men who did not take aspirin suffered from heart attacks. Twenty-six of them died.

The researchers said the doctors’ study provided clear proof（证据）that taking aspirin could prevent a first heart attack in healthy, older men. They said, however, the result did not mean every man over the age of fifty should take aspirin. They said aspirin couldn’t help men who did not eat healthy foods, who smoked cigarettes and who were fat. The researchers said men who thought they would be helped by taking aspirin should talk with their doctors first.

小题1:The passage tells us that the new use of aspirin is ______.

A．to treat heart disease

B．to reduce pain while one suffers from a heart attack

C．to help old people to be more healthy 　

D．to reduce the chance of a heart attack in old men小题2:Aspirin can help those who ______.

A．work as doctors

B．are under 40 years old

C．are fat and smoke cigarettes

D．are older and healthy小题3:At last the researchers advised us to take aspirin ______.

A．with care

B．as much as we like

C．every day

D．only considering the age小题4:From the experiment we can know that about ______ of people who suffered from heart attacks without aspirin died.

A．7%

B．11%

C．19%

D．44%

（14分）现有X、Y、Z、W、R五种元素，其中前四种为短周期主族元素。X原子的最外层电子数是核外电子层数的3倍，Y的最高正价与最低负价的代数和为6；X、Z同主族，W与X、Y均不同周期，R²⁺的价电子排布式为3d⁵。

（1）R元素在周期表中的位置              ；W₂X₂的电子式           。

（2）X、Y、Z的最低价氢化物中：沸点最高的是         （填化学式）；共价键键能最小的是         ；X、Y、Z的杂化类型        （填相同或不相同）。

（3）若R的晶体中每个晶胞平均含有2个R原子，请在下图晶胞中用•标出未画出的R原子。

（4）将1.19g ZXY₂溶于100ml水中发生非氧化还原反应，生成2种酸，反应方程式为                       ；所得溶液中阴离子浓度由大到小的顺序是                     。

眼球中的睫状体的作用是 [ ]

A．调节角膜的明暗

B．调节瞳孔的大小

C．调节晶状体曲度

D．调节眼睑开闭

混凝土浇筑前对模板钢筋应作哪些检查？

《安全生产法》规定，生产、经营、储存、使用危险物品的车间、商店、仓库必须与在同一座建筑物内的（）分开，并保持一定的安全距离。