1.at a low price以低价
e.g.:The fridge was bought at a low price.2.translate... into...把.....译成
e.g.:The book was translated into French.3.all of a sudden=suddenly 突然
e.g.:An earthquake took place all of a sudden in Sichuan.

被动语态(二)--一般过去时的被动语态
在第5单元已介绍了被动语态的概念及主动语态变被动语态的用法，本单元主要介绍一般过去时的被动语态。
一般过去时被动语态的结构:
肯定句:主语+was/were+动词的过去分词+（by.….） .e.g.:The classroom was cleaned by me yesterday afternoon.否定句:主语+was/were+not+动词的过去分词+(by.….).e.g.He wasn't sent to the city last month.

一般疑问句:Was/Were+主语+动词的过去分词+(by...）?回答用:Yes,主语+was/were;No,主语+wasn't/weren't。e.g.:—Was your homework finished last weekend?—Yes,it was./No,it wasn't.
特殊疑问句:
(1)当疑问副词/代词不作主语时:
疑问词+was/were+主语+过去分词+(by...)?e.g.:Where was the car parked?
(2)当疑问代词作主语时:
疑问代词+was/were+过去分词+(by...) ?e.g.:Who was taken to the office?