动词-ing形式的否定是在动名词前加not。
I'm sorry for not finishing my task on time.对不起没有准时完成任务。
I must apologize for not letting you know ahead of time.
对不起没有提前通知你。
That’s all right.
没关系。
Not knowing his telephone number, she had some difficulty getting in touch with Bill.
因为不知道比尔的电话号码，她和他联系遇到了困难。
