They have planted a lot of trees since 1990.变被动语态

He has planted a lot of trees.(改为被动语态） a lot of trees have been planted 变一般疑问句(并回答) /变否定句 We have planted many trees.改为被动语态 They were cutting trees变被动语态 初三英语改被动语态1.They planted more trees last month.2.We often see 改写句子 被动语态1.She has planted many trees on the hill.2.They are 将下列句子改为被动语态 we planted thousands of trees yesterday（一般过去时） They have collected stamps since 1986.改为被动语态 We planted many trees on the hill变成被动语态 She planted some pear trees last spring.(被动语态) 主动语态变被动1.they have set up a power station in their hometown2 They said that they would plant more trees. 变被动语态