请选择（61）处最佳答案。
A. force
B. volume
C. control
D. power
It is desirable that he_____.
A. gives up trying B. give up trying C. would give up trying D. is going to give up trying
This is one of the best books _____on the subject.
A. that have ever been written B. which have ever been written C. that has ever been written D. whatever have been written
It may be concluded that testing _____
A. should test only opinions B. Should always be written C. has changed since the Middle Ages D. is given only in factories
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