Fill in the blanks by using passive voice1.As we all know, both the Summer and Winter Olympic Games (held )every four year.2.The first Olympic Games (held)in Greece in 1896. 3.Mordern cell phones are more than just phones---they (use) as cameras and radios. 4.After years of hard work, parts of states (put) back together and missing pieces (replace).5.In order to protect the environment ,the number of visitors (should limit). are heldwas heldare being usedhave been puthave been replacedshould be limited语态 (voice) 是个语法范畴，它是一种动词形式，表示动词的主语与该动词所表示的动作之间的主动和被动关系。动词的被动语态由“助动词 be+ 及物动词的过去分词”构成。当主动句变为被动句时，原来的宾语变成了主语，原来的主语变成了介词 by 的宾语。We cleaned the classroom yesterday.昨天我们打扫了教室。The classroom was cleaned by us yesterday. 昨天教室被我们打扫了。一般现在时： am / is / are done一般过去时： was / were done一般将来时： shall / will be done ; be going to be done现在进行时： am / is / are being done过去进行时： was / were being done现在完成时： have / has been done过去完成时： had been done当句中含有情态动词时： can / must / have to…be doneHe is regarded as a brilliant. 他被认为很有才气。This book was written in 1969. 这本书是 1969 年写成的。The work will be finished in three hours. 工作将于三小时后完成。He told us the cat was being washed when we called him. 他告诉我们打电话时他正在给猫洗澡。The pen has been used for several years. 这支钢笔已经用了几年。He said the factory had been opened . 他说这家工厂已经开张。The baby must be looked after well. 这孩子必须被好好照顾。The broken bike is being repaired now. 那辆坏了的自行车正在被修理。不能转换为被动句的主动句1. 有些连系动词， feel, small, taste, sound, prove, remain.2. 有些及物动词，如 have, become （...
