被动语态小知识1

1 （is done/ was done）

先来比较被动和主动
somebody built this house in 1961 (主动)
This house was built in 1961 （被动）

主动语态用来说明动作的执行者，

被动语态用来说明动作的承受者，往往不知道或者不必知道动作的执行者，（如果需要知道，则可以用by ）例如

This house was built by my grandfather .

一般现在时

主动 clean(s) /see(s)等

somebody cleans this room every day .

被动 : am /is /are /+ cleaned /seen 等

This room is cleaned every day
Many accidents are caused by careless driving .

一般过去时

主动 ： cleaned / saw 等

Someboy cleaned this room yesterday .

被动 was /were +cleaned /等

This room was cleaned yesterday