一、利用主動和被動關系

這里說的主動與被動關系，指的是非謂語動詞所表示的動作與其邏輯主語之間是主動關系還是被動關系。若是主動關系，非謂語動詞就用主動式;若是被動關系，非謂語動詞就用被動式。下面分三類舉例說明：

1. 涉及不定式的主動與被動式

(1) I feel greatly honored _________ into their society. (北京卷)

A. to welcome B. welcoming C. to be welcomed D. welcomed

答案為C。be (feel) honored后習慣上接不定式，故可排除B和D;又因為I與welcome之間為被動關系，故用不定式的被動式。

(2) The message is very important, so it is supposed _________ as soon as possible. (陜西卷)

A. to be sent B. to send C. being sent D. sending

答案為A。be supposed后習慣上不接動名詞，而接不定式，其意為“應該做某事”，故可排除C和D;又因為“消息”與“傳達”之間為被動關系，故用被動式。

2. 涉及動名詞的主動與被動式

At the beginning of class, the noise of desks _________ could be heard outside the classroom. (全國II)

A. opened and closed B. to be opened and closed

C. being opened and closed D. to open and close

答案為C。由于desks與open和close的關系是被動關系，故要用被動式，可排除D;又因為用于介詞of后作賓語，所以要用動名詞，不用不定式或過去分詞，故可排除A和D，所以答案選C。

3. 涉及現在分詞的主動與被動式

_________ that she was going off to sleep, I asked if she’d like that little doll on her bed. (北京卷)

A. Seeing B. To see C. See D. Seen

答案為A。首先要排除B和C，因為B為不定式，它用于句首時，通常是表示目的，在此不合句意;而C為動詞原形，選它會構成祈使句，一是句意不通，二是這樣會導致前后兩句之間沒有連詞而出錯。在剩下的A和D之間，只能選seeing，不能選seen，因為句子主語是 I與see之間為主動關系，而非被動關系。

【注意】由于過去分詞本身可以表示被動，所以過去分詞不用被動式，同時它也沒有被動式。請看幾道相關的考題：

(1) The trees _________ in the storm have been moved off the road. (湖南卷)

A. being blown down B. blown down C. blowing down D. to blow down

答案為B。由于trees與blow down之間為被動關系，故要用過去分詞。blown down in the storm在此用作定語，修飾the trees，相當于定語從句which were blown down in the storm。

(2) To learn English well, we should find opportunities to hear English _________ as much as we can. (江蘇卷)

A. speak B. speaking C.spoken D. to speak

答案為C。由于English與speak之間為被動關系，故要用過去分詞。

(3) We finished the run in less than half the time _________. (江西卷)

A. allowing B. to allow C. allowed D. allows

答案為C。由于time與allow之間為被動關系，故要用過去分詞。in the time allowed意為“在規定的時間內”。