be always 后什么情况加doing还是do或does

be always 后什么情况加doing还是do或does be always doing和 be always do/does 有什么区别 be different from后加to do 还是doing your后(或前)加do还是does? cause后可以加什么 是to do还是doing thanks for后加什么?doing还是to do 1.He is always 后用DOING 还是DOES be always doing 还是always doing ‘must be’后加什么 加doing never后加doing还是to do enough后加doing还是to do suggest 后加doing 还是to do