搜题请搜索小程序“爱下问搜题”
问题 单项选择题 B型题

Ig同种异型决定簇存在于（）

A.VH、VL

B.CH、CL

C.CH2

D.CH3

E.CH4

答案

参考答案：B

解析：超变区是免疫球蛋白的可变区氨基酸组成及排列顺序变化最为剧烈的特定部位。

选择题

一五计划中，优先发展的是                        （   ）

A．重工业

B．轻工业

C．交通运输业

D．农业和商业
查看答案
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
查看答案