问题 单项选择题

患者红细胞在缺氧时变成镰形,是因为其血红蛋白为

A.HbA

B.HbA2

C.HbBart

D.HbF

E.HbS

答案

参考答案:E

解析: 镰形细胞贫血是一种常染色体显性遗传病,有Hbs形成,其在脱氧状态下形成多聚体。纤维多聚体排列方向与细胞膜平行,并与之紧密接触,当有足够的多聚体形成时,红细胞即会“镰变”。

阅读理解

A student is learning to speak British English. He wonders: Can I communicate with Americans? Can they understand me? Learners of English often ask: What are the differences between British and American English? How important are these differences?

Certainly, there are some differences between British and American English. There are a few differences in grammar. For example, speakers of British English say “in hospital” and "Have you a pen?” , Americans say “in the hospital” and ‘Do you have a pen?’.Pronunciation is sometimes different. Americans usually sound theirs in words like “bird” and “hurt”. Speakers of British English do not sound theirs in these words. There are differences between British and American English in spelling and vocabulary. For example, “colour” and “honour” are British, “color” and “honor” are American.

These differences in grammar, pronunciation, spelling and vocabulary are not important, however. For the most part, British and American English are the same language.

小题1:According to this passage, a student who is learning to speak American English might be afraid that __________.

A.British people cannot understand him

B.American people cannot understand him

C.the grammar is too hard for him

D.the spelling is too hard for him小题2: American English and British English are different in __________.

A.spelling

B.pronunciation

C.grammar

D.all of the above小题3:What is NOT mentioned(提及) in the passage?

A.Whether there are differences between British English and American English.

B.Whether British English and American English are one language or two.

C.How the differences between British English and American English came about.

D.How important the differences are.小题4:Most __________ say “Do you have a watch?”

A.British people   

B.Americans

C.children

D.teachers小题5:According to this passage, British people and Americans have __________ difficulty in understanding each other.

A.little

B.much

C.some

D.great

判断题