有机物在反应中,常有下列原子间的共价键全部或部分断裂,如C—H、C—C、C=C、

题型:选择题

问题:

有机物在反应中,常有下列原子间的共价键全部或部分断裂,如C—H、C—C、C=C、C—O、C═O等。下列各反应中,反应物分子中断裂键的排列,正确的组合是

化学反应乙醇酯化乙醇氧化丙烷取代乙酸酯化丙烯加成
AO—HC—HC—HC—OC=C
BO—HO—HC—CC═OC—H
CC—OC—OC—HO—HC—C
DC—OC—HC—CC—OC=C

考点:结构简式结构式
题型:选择题

最近的一项研究指出:“适量饮酒对妇女的心脏有益。”研究人员对1000名女护士进行调查,发现那些每星期饮酒3~15次的人,其患心脏病的可能性较每星期饮酒少于3次的人低。因此,研究人员发现了饮酒量与妇女心脏病之间的联系。 以下哪项如果为真,最不可能削弱上述论证

A.许多妇女因为感觉自己的身体状况良好,从而使得她们的饮酒量增加。

B.调查显示:性格独立的妇女更愿意适量饮酒并同时加强自己的身体锻炼。

C.护士因为职业习惯的原因,饮酒次数比普通妇女要多一些。再者,她们的年龄也偏年轻。

D.对男性饮酒的研究发现,每星期饮酒3~15次的人中,有一半人患心脏病的可能性比少于3次的人还要高。

E.这项研究得到了某家酒精饮料企业的经费资助,有人检举研究人员在调查对象的选择上有不公正的行为。

题型:选择题

阅读理解。

     Who is there among us who hasn't dreamed of having his or her own small (maybe, several years later),

even big business, and having wonderful freedom, both from a boss and from the time clock ; the freedom

to make up our own rules for our work, and our own plans -arranging our own hours of work? That way

work would be both painless and fun. Or, so we imagine.

     Well, in fact it isn't quite as simple as that. Yes, it is true that being the boss has its satisfactions and that

you can arrange your working hours freely if you own your own small business.  But in those early years of

starting your own business. you shouldn't think of a free day, not to mention flying off for a month's vacation.

It is not unusual for new business owners to work seventy or eighty hours a week, and if there is a day off,

that day might need to be devoted to accounting (算账).

     But this negative picture doesn't destroy the beautiful hopes. The possibility of getting something wonderful

in return-both material and mental-continues to drive that large number of people who start up small businesses

each yearin the United States.

1. From the first paragraph, we know that everybody hopes _____.

A. to rule others

B. to be his or her own boss

C. to get a time clock

D. to be free from work

2. Most new business owners have to _____.

A. work more than 10 hours a day

B. devote himself to accounting

C. fly to some places in the world

D. have a day off in a week

3. The expression "negative picture" most probably means"_____ ".

A. a terrible experience

B. a poor picture

C. limited freedom

D. unpleasant situations

4. The beautiful hopes will never be destroyed because _____.

A. people love beautiful things by nature

B. people have a strong desire to seek personal gains

C. small businesses make big money each year in the US

D. small businesses have advantages over big companies

题型:选择题

灭火机器人能够感知火源主要是利用了()

A.传感技术

B.通信技术

C.计算机技术

D.纳米技术

题型:选择题

中国人有不同于西方人的另一种信仰,这信仰称之为“良知”。

题型:选择题

宾馆应在客房内设置消防提示牌,明确规定()。

A、禁止使用消防设施

B、禁止使用自带用电器具

C、禁止卧床吸烟

D、禁止使用电热器具

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