He is never behind with [in] his work. 他从不拖拉。
He was behind in [with] his rent. 他拖欠了房租。
He helped a classmate who was behind with his homework. 他帮助一位没有按时完成作业的同班同学。
2. be behind in doing sth 做某事不落在后面。如：
The boy is behind in handing in homework. 这孩子没能按时交家庭作业。
He was never behind in offering suggestions. 他提建议从来不落在别人后面。
3. from behind 从后面。如：
He held her from behind. 他从后面抱住她。
They attacked us from behind. 他们从后面攻击我们。
注：有时 behind 是介词，其后可接宾语。如：
He came out from behind the door. 他从门后出来。
4. fall [drop] behind 落在后面。如:
I’ve fallen behind in work. 我工作落后了。
Some students dropped behind in their studies. 有的在上落在后面。
5. leave sth behind (某人)走后留下(掉下)某物。如：
What have we left behind? 我们走后留下什么了?
He left his umbrella behind. 他离开时没有把雨伞带走。
6. stay [remain] behind 留下，在别人后面留下。如：
He alone remained behind. 只有他一个人留下没走。
I had to stay behind after school. 放学后我还得留在学校。
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