She won't do her homework until her mother comes back.答案是won't改为will理由是until主句只能接延续性动词的肯定式谁能帮我解释一下吗
热心网友
先弄清楚他们的含义: until 直到...... 为止 (动作持续一段时间后结束,谓语动词必须是延续性的) not until 直到...... 才......(动作才发生, 谓语动词必须是短暂性的)例如: We will stay here until he comes back.(我们将呆在这儿直到他回来) We won't leave here until he comes back.(我们直到他回来才离开.)
热心网友
until 直到...... 为止 (动作持续一段时间后结束,谓语动词必须是延续性的)not until 直到...... 才......(动作才发生, 谓语动词必须是短暂性的)She won't do her homework until her mother comes back.中do one's homework是延续性动词，自然不能用not until所以用改为won't