He is doing his homework为什么该句中的doing用原形

Tom is busy now.He is doing his homework at home now的同义句 Tom is busy now.He is doing his homework at home.改为两句重合 He is doing his homework 中文 He is doing his homework .翻译 he is()doing his homework速求! He is j___ doing his homework He is b_____ doing his homework he is doing his homework 改复数 he is ()his grandparents'home用介词 he is doing something fun he is meeting his friends He is doing his homework.He said改为宾语从句 --What is he doing for vacation?---He____(relax) at home. he is doing his homework.[doing his homework]一般疑问句,否定句,划线提问,否回 将下列句子改为含宾语从句的复合句what's her name?the teacher askedthe teacher asked what - - -ls he doing his home work?jim askedjim asked - - - doing his homeworkhow old is the woman?no one knowsno one knows - - - - - is he homework doing his连词成句 He is doing his homework now.Don't b___him He is j___ doing his homework.求快啊,今晚要交! He is doing his homework with me的复数