本人选择的答案填在横线上，准确答案写在外面，请高手针对本人的错误给与解析，多谢
17. If you can’t see the words written on the blackboard very well, maybe you need _A___.B
A. examining your eyes
B. to have your eyes examined
C. to have examined your eyes
D. to be examined your eyes
18. __B__ many times , but he still couldn’t use the computer.C
A. Though he had been taught
B. Having been taught
C. He was taught
D. Having taught
19. __A__ the film may be , I haven’t any interest to see it.D
A. No matter exciting
B. Although exciting
C. Even if excited
D. However exciting
20. There’s Mr silver a big fellow who gets _D___ for everything; ther’s Mrs Silver , who does all the ____.A
A. blaming …blaming
B. blamed …blame
C. blamed…blame
D. blamed…blaming
27. To learn to skate skillfully__A___.C
A. much practice is needed
B. much practice are needed
C. one needs much practice
D. one is needed much practice
28. Electicial resistance is a common property of all materials __A__.C
A. only differs in degree
B. only in degree in differs
C. differing only in degree
D. and differing in degree only
29. _B___, Hong Kong acts as a gateway into and out of Taiwan.A
A. Strategically located
B. It is located strategically
C. Where strategically located
D. Because located strategically

17. need doing sth需要被...(主动形式表达被动含义,相当于need to be done);need to do sth需要去做某事,本题中主句为you需要让眼睛接受检查,故选B. to have your eyes examined ,如果把题目中的you改为your eyes,就要选A了

18.题目中有but的存在,本题中but是个连词,起连接两个句子的作用,故而选B-一个完整的句子,如果把题目中的but去掉,则选C.

19. 无论电影大概会多有趣,However exciting the film may be 或No matter how exciting the film may be , 此处的however不做然而解释,而相当于no matter how

20. 很抱歉,这道题如果让我来填的话,我会都填上blamed,所以爱莫能助.

27. To learn to skate skillfully是个目的状语,它的逻辑上的主语必须是主句的主语,所以答案只能是CD中产生,因为practice是不可能做这个状语的主语的,当然D明显在主被动上存在问题,故选C

28. 这个句子没有任何连词的存在,故而只能有一个谓语动词,而句中已经有了谓语is,那么其它动词只能处理成非谓语,所以是C,如果选A的话,则需要给句子加个连词,比如说 which

29. 这道题和18题的道理是一样的,只是反了过来,这题里没有连词,所以不能用B,而只能用A(非谓语),如果Hong Kong 前加个连词so,那就用B