非谓语讲解
问题描述：
非谓语讲解
i heard her crying when i walking past.
i sat near her and heard her sing the new song.
谁能给讲下这里hear 后面跟动词用这两种形式是为什么啊?
答
hear sb do听见某人做某事（做过）
hear sb doing听见某人正在做某事