中和抗体抗病毒的机制是（） A.直接杀伤病毒 B.阻止病毒吸附和_爱下问搜题

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问题单项选择题 A1/A2型题

中和抗体抗病毒的机制是（）

A.直接杀伤病毒

B.阻止病毒吸附和穿入

C.阻止病毒脱壳

D.阻止病毒核酸转录

E.阻止病毒核酸复制

答案

参考答案：B

解析：中和抗体在病毒免疫中起主要作用、其作用机制主要是改变病毒表面的构型，阻止病毒吸附于易感细胞，使病毒不能穿入易感细胞内进行增殖。

完形填空

完型填空。

Dear Annie,
     Thank you for your   1   . I'm   2    you like your school.
     I   3   to school from Monday to Friday.   4 have four classes in the morning and two classes in the afternoon.
We have many things to do     5 class.    On Monday and Wednesday afternoon we have sports.   On Tuesday
afternoon some of    6 have a singing class and on Thursday afternoon some have a drawing class. On Friday
afternoon we practise(练习)  7    English. My Chinese friends would like to   8   with me in English. They think I
am like an English   9   . Isn't it great?
     On Saturdays and Sundays I don't go to school. Very often(经常) I go to the parks and have a good time   10
my family there.
                                                                                                                                                                                      Yours,
                                                                                                                                                                                      Henry

( )1.A.book
( )2.A.sorry
( )3.A.go
( )4.A.We
( )5.A.after
( )6.A.them
( )7.A.saying
( )8.A.tell
( )9.A.student
( )10.A.in

B. pen
B. fine
B. like
B. You
B. before
B. you
B. telling
B. talk
B. boy
B. with

C. letter
C. glad
C. have
C. They
C. for
C. me
C. speaking
C. say
C. girl
C. of

D. bike
D. good
D. want
D. Teachers
D. in
D. us
D. listening
D. have
D. teacher
D at

判断题

柴油机磨合运转后，不需要更换机油。