MY mother always frogot the door, but she remembered when
she left yesterday.
用 TO DO DOING 填空
我认为都是TO DO
參考答案:remenber与forget的用法比较简单，我们只需记住这么一点：那就是，后面跟不定式to do表示动作尚未进行，跟动名词doing表示动作业已完成。例如：
MY mother always frogot TO LOCK the door, but she remembered LOCKING IT when she left yesterday.