are doing some reading为什么doing和reading要同时加ing?

They are doing some reading.改为一般现在时 They are doing some very important ( ) (work) They are doing some English _(练习). We are doing some cleaning now.对doing some cleaning提问 what are the children doing?------are running,------are dancing..A,some ,others B,some,other washing,doing,are,some,they?（连词成句） They are doing some exercise ______a PE lessonAat Bin Con we are doing some (read)for the exams In some places,what are the people doing?怎样回答 some children are doing a dragon dance翻译 They are doing some cleaning now.其中 为什么用are doing 而不用are going to呢? are doing some reading为什么doing和reading要同时加ing? They are doing some exercise with Mr Ma 为什么用doing 英语翻译：There are some really mean people there saying and doing some really mean things some people are doing sth others are doing another thing 然后就是 these people 和 thepeople的区别 most of the children are playing,while some are still doing their homeworkmost of the children ______ ______,while some are still doing their homework Some students are reading English,while o___ are doing math problems What are the __(policeman) doing?They are talking to some people.为什么