[例1]We were not surprised at______，for he had worked so hard.
A.what has he achieved B.that what he had achieved
C.what he had achieved D.that he had achieved
【解析】答案C。at是介詞，其後接賓語從句時，從句要用陳述句的語序。achieve是及物動詞，what在從句中作賓語，所以選C。that在從句中隻起連接作用，無意義。
[例2]______I saw was two men crossing the street.
A.What B.Whom C.Who D.That
【解析】答案A。本句中的主語是主語從句，what在從句中作賓語。
[例3]Would the news______he failed to pass the exam bother you？
A.which B.that C.of which D.on which
【解析】答案B。由於從句he failed to pass the exam 是news的內容，所以這是一個同位語從句，應該用that引導。
[例4]The fact ______he does so in so short period of time challenges explanation.
A.why B.that C.what D.which
【解析】答案B。fact後的從句講的是fact的內容，所以是同位語從句，引導同位語從句的連詞隻能使用that。
[例5]The old gentleman never fails to help______is in need of his help.
A.whom B.who C.whoever D.whomever
【解析】答案C。本句中需要填入一個連接代詞引導賓語從句，且此代詞要在從句中作主語。A、D都隻能作賓語。whoever引導賓語從句。who也可以引導賓語從句，但whoever強調無論誰。
[例6]______was unimportant.
A.Whether he enjoyed our dinner or not
B.No matter how he enjoyed our dinner
C.If he enjoyed our dinner
D.What he enjoyed our dinner
【解析】答案A。本句中包含一個主語從句，意思是“他是否喜歡我們的飯不重要”。隻有A最符合題意。B、C中的No matter how 和If 都引導狀語從句；D項中的what在從句中作主語或賓語，而本從句中有主語和賓語。
[例7]How long do you think______to finish this urgent task？