例題分析：15.It is politely requested by the hotel management that radios ______ after 11 o'clock at night.

　　A. were not played 　　B. not be played

　　C. not to play 　　　　D. did not play

　　全句意思是：“旅館管理部門懇請客人晚上11點后不要打開收音機”。句中的謂語動詞request(請求)所引出的從句應(yīng)當用虛擬語氣，即動詞原形或“should+動詞原形”。本句的主語從句中，主語radio是謂語動詞play 的客體，謂語應(yīng)當用被動語態(tài)。所以，答案是C) not be played。在上述這類句子中不能用動詞過去時形式表示虛擬語氣，所以A)不正確。選項B) not to play是動詞帶to的不定式，不能在句中作謂語。選項D)did not play也是動詞play的過去時形式，同樣不能在本句中作為虛擬語氣來使用。而且，它是主動語態(tài)形式，而本題要用被動語態(tài)。

　　練習(xí)：

　　16). The chairman requested that .

　　[A]the members studied more carefully the problem

　　[B]the problem was more carefulnessly studied

　　[C]with more carefulness the problem could be studied

　　[D]the members study the problem more carefully

　　17). The committee recommends that the matter at the next meeting .

　　[A]would be discussed

　　[B]will be discussed

　　[C]be discussed

　　[D]may be discussed

　　18). The doctor insisted that his patient .

　　[A]that he not work too hard for three months

　　[B]take it easy for three months

　　[C]taking it easy inside of three months

　　[D]to take some vacations for three months