成人高考网上培训视频

3. ____is well-known， the earth moves around the sun.()

A. Which

B. What

C. As

D. It

【答案】C

【考点】考查as引导的非限制定语从句;

【解析】as和which在用法上有区别，which一般放句中，而as一般放句首，且有“正如……”之意。故本题选C。

4. The harder you work， ____.()

A. the more you learn

B. you learn the most

C. the most you learn

D. you learn the more

【答案】A

【考点】本题考查the 比较级。 ;

【解析】the 比较级，表示“越……越……”句子意思是“你越努力，得到的就越多。”故本题答案选A。

5. Only then ____ that he had left his key on his office.()

A. he realized

B. did he realize

C. had he realized

D. he had realized

【答案】B

【考点】本题考查倒装结构;

【解析】“only 状语从句”位于句首，句子发生部分倒装，即把助动词放在主语前面。then表示在过去，故用did。所以本题选B。