what were you doing 为什么是were不是what

what were you doing 为什么是were不是what 为什么是What were you doing,是过去式为什么要用doing,不是what were you do what were you doing? Do you remember what you were doing? what kind of work were you doing? tell everyone what you were doing wrong what were you doing __your father__back? what were you doing _______(昨天晚上） what were you doing yesterday什么时态 what were you doing this morning what were you doing when he arrived what did you do 与what were you doing