分子式为 C.5H10的烯烃共有(要考虑顺反异构体)() A.5种 B.6种 C.7

题型:单项选择题

问题:

分子式为C.5H10的烯烃共有(要考虑顺反异构体)()

A.5种

B.6种

C.7种

D.8种

考点:化学工程分析化学概论分析化学概论题库
题型:单项选择题

Researchers have announced 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.

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 forty and eighty-four. More than 11,000 of the doctors took a harmless 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 didn’t take aspirin suffered from heart attacks. Twenty-six of them died.

The researchers said the doctors’ study provides clear proof that taking aspirin can prevent a first heart attack in healthy, older men. They said ,however, the result does not mean every man over the age of fifty should take aspirin. They said aspirin couldn’t help men who do not eat healthy foods, who smoke cigarettes and who are fat. The researchers said men who think 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:From the experiment we can conclude that about _________ of people who suffered from heart attacks without aspirin died.

A.7%

B.11%

C.19%

D.44%

题型:单项选择题

走钢丝的杂技演员要使自己更稳一些,他们都是使 [ ]

A.重心低一些

B.重心高一些

C.走的快一些

D.高高举起手中拿的铁棒

题型:单项选择题

影响心脏浊音界改变的是

A.主动脉瘤

B.心包积液

C.肺气肿

D.以上均不是

E.克山病

题型:单项选择题

学校里买了675米红、蓝、黑三种布料.做校服用去二分之一红布,三分之二蓝布和四分之三黑布,剩下的各种颜色布的数量相等.问三种颜色的布各买多少米?  

题型:单项选择题

能引起恒温动物体温升高的物质是  

A.钙离子

B.白细胞介素-1

C.精氨酸加压素

D.脂皮质蛋白1

E.α-黑素细胞刺激素

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