we began to plant trees at nine 改为否定句 为什么呀

we began to plant trees at nine 改为否定句 we began to plant trees at nine 改为否定句 为什么呀 sarah can plant trees 改为否定句 Go to bed at nine o'clock.改为否定句 They wanted to plant trees.改为否定句 一般疑问句 并做两种回答 I must plant more trees 如何改为否定句 At about nine o'clock they b___ to plant trees the day befor we are going to plant some flowers on the farm 改为否定句 How are Rick always goes to school at nine fifty.(改为否定句) We can (plant trees) (in the park ) 改否定句 一般疑问句 否定回答 括号提问 将here,we,can,trees,plant?组成Can we plant trees here?为什么要这样组句? we are going to plant more trees next year改为被动语态.