He---back until the work---done.
A.isn't;will be B.won't be;will be C;won't be;is 为啥选C不选A
选项是C
因为【主将从现】.主句用【一般将来时】,从句用【一般现在时】.won't 是什么东西，是什么的缩写，还是过去式？won't 是will not的缩写.