doing a homework 与doing homework谁对

doing a homework 与doing homework谁对 doing homework, the are doing their homework.对doing their homework提问 I'm doing my homework.对doing my homework提问 we are doing homework对doing homework提问 lily is doing her homework对ding her homework提问 His sister is doing her homework 对her homework 提问 A and B are doing their homework. 对A and B提问 答案who is doing They are doing their homework?对doing their brother homework is doing doing his homework是什么意思 I'm busy doing my homework 对doing my homework 提问