问题 单项选择题 A1型题

溶血性链球菌或癌细胞分泌哪种物质可破坏基质的防御屏障()

A.胶原蛋白酶

B.透明质酸酶

C.弹性蛋白酶

D.基质金属蛋白酶

E.碱性磷酸酶

答案

参考答案:B

解析:基质中透明质酸含量最多,与多糖相结合可形成分子筛立体结构,起到局部屏障作用。溶血性链球菌或癌细胞能分泌透明质酸酶,降解透明质酸,从而使屏障解体。

阅读理解

Read and choose. (选择正确的答案) 

     Bob is a middle school student. He studies in a middle school in the east suburbs (郊区) of California.

Bob goes to school from Monday to Friday. On weekdays, he always gets up at 7:00 o'clock, then he

has breakfast. He usually has a cup of milk, a piece of bread and two fried eggs for his breakfast. At

about 8 : 00 0'clock, he gets into his father's car and his dad drives it down the road towards his school.

Classes begin at 8 :30 and at 12 :30, he goes to the school canteen for lunch. In the afternoon,  when

classes are over,  Bob usually plays basketball with his classmates. Sometimes he also goes to the school

library to do some reading. In the evening, Bob may either watch an interesting TV program or do some

Internet surfing(冲浪). He goes to bed at 10 :00. His school days are busy, but he always enjoys them

very much.

1. Where does Bob live?          

A. He lives in a school.

B. He lives in California.

C. He lives in China.

2. How many days does Bob go to school in a week?              

A. Seven days.          

B. Six days.          

C. Five days.

3. Does Bob go to school by bus?           

A. No, he doesn't. His father drives him to school.

B. Yes, he does.

C. No, he doesn't. He goes to school by bike.

4. What does Bob do after classes?              

A. He goes home.

B. He plays basketball everyday.

C. He usually plays basketball and he also goes to the library.

5. Does Bob like his schooldays?              

A. Yes, he does.

B. No, he doesn't.

C. Just so-so.

6. What's the Chinese meaning of the word "canteen" ?           

A. 搡场                

B. 餐厅            

C. 图书馆

单项选择题