Your homework must be handed in today改为主动语态 Thepostcards have been sent by his sister 改为一般疑问句The test is very difficult,so many students can't understand it同义句转换The children are looked after carefully改为同义句 英语
网友回答
【答案】 1、You must hand in your homework today
2、Have the postcards been sent by his sister?
3、Many students can't understand it because the test is very difficult
4、The children are taken care of well