C. Told D. He had been told

　　解析：本题的关键词是but , 有but 证明前后是两个并列句，这两个并列句都必须有自己的主语和谓语， 故⑵答案为D . 而⑴前后是一个主从复合句，表示让步关系， 由现在分词的完成时来替代从句，故选B.

　　17. .⑴It is only by practicing English for several hours every day _________be able to use it freely.

　　⑵Only by practicing English for several hours every day _________be able to use it freely .

　　A. will you B. may you

　　C. that you will D. when you must

　　解析：⑴考察的是强调句型 ， 强调介词短语only by practicing English ，强调句中不用倒装。 故选C. ⑵考察的是"only+介词短语、副词、从句"放在句首，要求用部分倒装。 故选A。

　　 18. ⑴- This is one of the books on this subject that ______________been written in Chinese.

　　⑵This is the only one of the books on this subject that ______________been written in Chinese .

　　 A. have B. had C. has D. having

　　解析：本题考察的是定语从句中谓语动词的选择， 从句谓语动词的选择关键要看其先行词。⑴ 的先行词the books是复数， 故选A 。⑵的先行词是the only one of the books 是单数， 故选C。

　　19. ⑴-------Where is your uncle's home ?

　　 -------In New York. But he _______in Boston for four years.

　　⑵-------Where is your uncle's home?

　　 -------In New York. And he _______in New York for four years.

　　A. has lived B. had lived w.w.w.302edu.c.o.m

　　C. lived D. had been living

　　解析：本题考察的是时态题。两题均有In New York.⑴的关键词是后文in Boston for four years 说明住在Boston 是过去的事实， 故选C 。⑵的关键是下文的in New York for four years 说明已经在New York 住了四年，有可能继续住下去， 故选A。

20. ⑴ The car manufacturer is much more productive. This year's production is three times ___________it was five years ago.