【语法透视】：含情态动词的被动语态1.含情态动词的被动语态的基本结构为“情态动词+be+及物动词的过去分词”。Many trees should be planted on the mountains. 应该在树上植许多树。Students should be allowed to go to school by bike.应该允许学生们骑自行车上学。2.把含情态动词的主动句变成被动句，即把“情态动词+动词原形”改为“情态动词+be+过去分词”，此时，作主语的要用动词承受者。We should clean the classroom every day. The classroom should be cleaned every day. 3.句式的转换(1)否定句：在情态动词后加not就行。These books cant be read for children. 这些书孩子们不能读。(2)一般疑问句：直接将被动语态的陈述句的情态动词提到的句首。Should Ann be allowed to wear her own clothes? 应该允许安选择自己的衣服吗？(3)特殊疑问句：由疑问词加上含有情态动词的被动语态的一般疑问句构成。When must my homework be handed in? 我的作业必须何时交？4.对含有情态动词的被动语态的一般疑问句的回答， 一般应保留原句中的情态动词，但must表示“必须”时，其否定回答用neednt。Should my homework be finished today? 我的作业应在今天完成吗？Yes, it should./No, it shouldnt. 是的，应在今天完成。/不，不应在今天完成。Must the room be cleaned right now? 房间必须马上打扫吗？Yes, it must./No, it neednt. 是的，必须立即打扫。/不，不必立即打扫。典例题解例1Teenagers should to choose their own clothes. A. allow B. to allow C. be allowed D. allowed解析C。主语teenagers是动作allow的承受者，再根据should确定要用情态动词的被动语态，即“情态动词+be+过去分词”。例2-What should we do first if we want to develop our village?-A lot of new roads , I think. A. have to build B. must build C. have built D. must be built解析D。new roads是动作build的承受者，应用被动语态。含must的情态动词的被动语态为“must+be+情态动词”。例3This kind of food_cool, clean and dry according to the instruction. A. should be carried B. must be put C. should be placed D. must be kept解析D。根据句意，主语food是动作的承受者，用被动语态，而空格后的cool是形容词，而“keep+某物+形容词”意为“使保持状态”，故选D。例4Smoking _ in public places, so dont smoke here. A. allows B. is allowed C. doesnt allow D. isnt allowed解析D。主语smoking是动作allow的承受者，排除A和C。由so dont smoke here可知这儿禁止吸烟，故选D。语法精练 I. 用括号内所给单词的适当形式填空。1.How many magazines _(can borrow) in your library every week?2.In many countries, teenagers under 18 _(should not allow) to go into Internet bars. 3.Some people think trees _(should plant) on Tree planting Day only. 4.The flowers _(must water) every day. 5.A dictionary _(can use) in the exam. II.同义句转换，每空一词。1.Students should clean their classroom every day. Their classroom _ _ _ every day. 2.Can you mend this radio?_ this radio _ _?3.We should not allow fifteen-year-olds to work at night. Fifteen-year-olds _ _ _ to work at night. 4.Who should be asked to volunteer at your local school? Who should _ _ to volunteer at your local school?5.They grow tea in the southeast of China. Tea _ _ in the southeast of China. III.根据汉语提示，完成下列句子。1.Many tall buildings _(可以看见)everywhere in our city. 2.All the work _(应该做) as soon as possible. 3.Waste-paper _(不应该扔)here. 4._rice_(能种植) in winter?5._the letters _(必须打) this afternoon?参考答案I.1.can be borrowed 2.shouldnt be allowed 3.should be planted 4.must be watered 5.can be used II.1.should be cleaned 2.Can, be mended 3.shouldnt be allowed 4.you ask 5.is grown III.1.can be seen 2. should be down 3.shouldnt be thrown 4.Can, be grown 5.Must, be typed