龋病为牙齿硬组织被何种微生物感染( )A．病毒 B．细菌 C．

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问题单项选择题

龋病为牙齿硬组织被何种微生物感染( )

A．病毒

B．细菌

C．真菌

D．支原体

E．以上均不正确

答案

参考答案：B

解析：就病因角度来说，龋病也可以称为牙齿硬组织的细菌感染性疾病。

句型转换

将下面句子改为同义句.(

1. A. It's rude to point at anyone with your chopsticks.

B. It's _____ _____ point at anyone with your chopsticks.

2. A. We should keep our classroom clean and tidy.

B. Our classroom should _____ _____ clean and tidy.

3. A. It's raining hard, so we have to stay here for a while.

B. It's raining _____ hard _____ we have to stay here for a while.

4. A. The little boy stopped crying and listened to music.

B. The little boy didn't cry _____ _____ and listened to music.

5. A. There is only a desk in the room.

B. There is_____ _____ a desk in the room

单项选择题

当呼叫过程中有切换发生，则（）

A.总是在另一小区分配一个新的频点

B.原来的话路并不释放直到MS在新的信道上发出成功信息

C.总是需要HON（HandoverNumber）

D.以上皆是