11.He was busily engaged ______ writing letters.

　　A. on 　B. in 　C. with 　D. by

　　12.Do remember to ______ the light when you leave the room.

　　A. turn up 　B. turn on 　C. turn off 　D. turn down

　　13.The atmosphere consists of an ocean of gases ______ miles high.

　　A. hundreds 　B. hundreds of 　C. of hundreds 　D. of hundreds of

　　14.Not only the students but also the old teacher ______ been changed.

　　A. was 　B. were 　C. has 　D. have

　　15.—— ________ I had!

　　—— You really suffered a lot.

　　A. What a time 　B. What time 　C. How a time 　D. how time

　　答案：

　　11.正確答案：B答案解析：be engaged in：從事，忙于。

　　12.正確答案：C答案解析：根據(jù)句意，應(yīng)該選擇“關(guān)閉”。句意：離開房間時一定記著把燈關(guān)掉。

　　13.正確答案：B答案解析：譯文：大氣由上百英里高的氣體組成。“hundred，thousand等數(shù)詞的復(fù)數(shù)形式+of短語”表示的是不確切的數(shù)量。

　　14.正確答案：C答案解析：not only…but also…是固定搭配，意思是：不但……而且……。它需要遵循就近原則，謂語動詞應(yīng)與the old teacher一致，所以答案是C.

　　15.正確答案：A答案解析：感嘆句分兩類：

　　1：What + n.+主謂部分2：How + adj. / adv. / v.+主謂部分。本題屬第一種，但省略了bad，相當(dāng)于 What a bad time I had! 這是個習(xí)慣用語。