[考题6] The research is so designed that once ____ nothing can be done to change it. (2002)
A. begins B. having begun C. beginning D. begun
[答案] D
[解析] once后省略了it（指前面刚被提及的the research） is，下划线表示一个“（研究）被开始、被启动”的被动的动作，应该采用过去分词的形式，因此本题选D。注意：本题题干中省略的it/the research is是顺承上文而自然进行的省略，被省略后仍可以很清楚地把握，而且使得整个句子更为简练。
[考题7] He speaks English well indeed, but of course not ____ a native speaker. (2004上海)
A. as fluent as B. more fluent than
C. so fluently as D. much fluently than
[答案] C
[解析] but在本题中作并列连词连接两个分句，后一分句属于省略句，后一分句中为了避免重复省略了主句中的主语he和比较状语从句中的谓语speaks English，由此可以看出题干中在对he和a native speaker说英语的程度进行比较。说英语的程度的比较应选用副词fluently，应首先排除选项A、B；much fluently than中than前面没有出现fluently的比较级的形式，应进一步排除选项D而选出C。
[考题] No matter how frequently ____, the works of Beethoven still attract people all over the world. (2006广东)
A. performed B. performing C. to be performed D. being performed
[答案] A
[解析] 题干中让步状语从句的原型为no matter how frequently they are performed（无论这些作品是如何经常地被表演），其中的they are可以省略。
本章补充强化训练题
1. — Are there any English story books for us students in the library?
— There are only a few, ____.
A. if any B. if there C. if some D. if has
2. — Would you like to go with us?
— Yes, ____.
A. I‘d B. I‘d like C. I‘d like to D. I‘d like to do
3. — Would you like to have a try once again?
— ____.
A. Yes, I like B. No, I don’t like it
C. Yes, I want very much D. Yes, I’d like to
4. — What do you think made Mary so upset?
— ____ her bicycle.
A. As she lost B. Lost
C. Losing D. Because of losing
5. — When did they get down to the job?
— ____.
A. Until they left B. Till they arrived
C. Since they finished it D. Not until they turned to me
6. — Are you angry?
— Yes. He should at least answer when ____.
A. speaking B. spoken to C. spoken D. speaking to
本章补充强化训练题参考答案
1.A 2.C 3.D 4.C 5.D 6.B