问题 单项选择题 A1型题

下列哪一项不是红细胞具备的生理特性()。

A.悬浮稳定性

B.趋化性

C.变形性

D.渗透脆性

E.膜通透性

答案

参考答案:B

解析:哺乳动物的红细胞无核、双凹碟状,呈圆盘形,是各种血细胞中数量最多的一种。红细胞的生理特性包括膜通透性、变形性、悬浮稳定性和渗透脆性。因此,趋化性不是红细胞具备的生理特性。

多项选择题
单项选择题

There is virtually no limit to how one can serve community interests, from spending a few hours a week with some charitable organization to practically full-time work for a social agency. Just as there are opportunities for voluntary service (1) (VSO) for young people before they take up full-time employment, (2) there are opportunities for overseas service for (3) technicians in developing countries. Some people, (4) those who retire early, (5) their technical and business skills in countries (6) there is a special need.

So in considering voluntary or (7) community service, there are more opportunities than there (8) were when one first began work. Most voluntary organizations have only a small full-time

(9) and depend very much on volunteers and part-timers. This means that working relationships are different from those in commercial organizations, and values may be different. (10) some ways they may seem more casual and less efficient, but one should not (11) them by commercial criteria. The people who work with them do so for different reasons and with different (12) , both personal and (13) . One should not join them (14) to arm them with professional experience; they must be joined with commitment to the (15) , not business efficiency. Because salaries are (16) or non-existent many voluntary bodies offer modest expense. But many retired people take part in community service for (17) , simply because they enjoy the work.

Many community activities possible (18) retirement were also possible during one’s working life but they are to be undertaken (19) seriously for that. Retired people who are just looking for something different or unusual to do should not consider (20) community service.

18()

A.before

B.on

C.in

D.at