把句子中的动词前加be动词（be动词有am/is/are），再把这个动词改成过去分词，然后把动作执行者放到句尾就好。举例：She invited her friends to go （她邀请她的朋友去购物。）改成被动语态，就是She was invited to go shopping by her （她被她的朋友邀请去购物）。其中her friends（她的朋友）是动作的执行者，所以把her friends放在末尾，前面再加一个by。在举几个：①He gave a book to （他给了她一本书）。被动：He was given a book by （他被她给了一本书）②He helped his friends to do （他帮他朋友写作业）。被动：He was helped to homework by his （他被他的朋友帮忙写作业。）
把主动语态改为被动语态，可以遵循以下几个步骤： 把宾语变成被动语态中的主语； 找出谓语动词，变成相应的被动。如：一般式变成be done。过去式变成was/were done； 把主语变成介词by 的宾语； 注意人称、时态和数的变化。 例： Bruce writes a letter every →A letter is written by Bruce every Li Lei mended the broken bike this →The broken bike was mended by Li Lei this He has written two novels so →Two novels have been written by him so They will plant ten trees →Ten trees will be planted by them Lucy is writing a letter →A letter is being written by Lucy You must lock the door when you →the door must be locked when you
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