问题 单项选择题

决定Ig的类和亚类的部位是( )

A.VL+VH
B.VL+CL
C.铰链区
D.CH
E.CL

答案

参考答案:D

解析: 根据免疫球蛋白重链恒定区肽链抗原特异性的不同,可将Ig分为IgG、IgA、IgM、 IgD、IgE五个类,根据轻链恒定区肽链抗原特异性的不同,各类Ig可分为κ和λ两种型,VH和 VL是抗原结合部位,铰链区结构的柔韧性允许抗体分子的抗原结合部位随意改变方向,使抗体分子结合抗原的能力大大增强。根据同一类Ig分子铰链区氨基酸组成和重链二硫键数目和位置的差异,又可分为亚类。

完形填空

Small talk is a good way to kill time and make friends. If you travel to other countries, do you know what to say to        small talk with local people?

In Britain the best topic is the weather. British        changes quite often. It’s a safe topic. You can start small talk simply by saying “It’s a lovely day today, isn’t it?”      the weather, it’s good to talk about gardens with English people. For example, you could say, “Those roses look really beautiful,       ?” English people love their pets. So it’s also nice to begin with “What a lovely        ! What’s its name?”

In America, people like to talk about sports,        Amecican football and basketball. They also talk about clothes by saying “It’s a nice shirt! Where did you get it?” The weather is a        topic there, too.

Of course, you should avoid a lot of topics during small talk in western countries. Don’t ask people “How old are you?”. Age is usually secret ,        for women.        ask “How much money do you make?” It makes people uncomfortable. Don’t ask strangers whether they have a girlfriend         boyfriend. Politics(政治) and religion(宗教) is not a good topic for two people who have just met, either.

小题1:A. end                    B. start                        C. speak

小题2:A. weather                    B. people                      C. food

小题3:A. Besides                 B. Except                      C. But

小题4:A. isn’t it                   B. aren’t they                 C. don’t they

小题5:A. picture                 B. dog                     C. boy

小题6:A. the same as             B. so that                    C. such as

小题7:A. safe                        B. dangerous                    C. hard

小题8:A. extremely                  B. especially                  C. exactly

小题9:A. Never                   B. Usually                  C. Please

小题10:A. with                  B. and                     C. or

单项选择题