have to+动词不得不做某事

　　表示“不得不做某事”，强调动词的“强行”成分。虽然不是助词，但经常会被当成助词来用，过去式为 had to,将来时为 will have to。

　　例句：

　　I'm sorry, but I have to cancel my reservation.

　　对不起，我不得不取消晚上的预约了。

　　I have to go now.

　　我现在必须得走了。

　　I have ( got ) to go. I'll call you later.

　　我必须得走了，回头见。

　　I have to tell you ( something ) . I love being alone.

　　我得告诉你点事情。我喜欢独处。

　　Act your age. You have to grow up.

　　能不能成熟点。你得学会长大了。

　　Do I have to make a reservation?

　　我必须要预约吗？

　　Do I have to wait here until she gets in?

　　我必须要在这等她回来吗？

　　It's totally my fault. You don't have to say you're sorry.

　　都是我的错，你不用说对不起。

　　对话：

　　A: You don't have to say you're sorry.

　　你不必说对不起。

　　B: Sure I do. It was all my fault.

　　必须的，都是我的错。

　　A: I have to leave right away for the meeting.

　　我得马上去开会了。

　　B: I'll catch up with you later.

　　我回头联系你。

　　A: I'd be pleased if you could join us for dinner.

　　如果你能和我们共进晚餐就太好了。

　　B: I'll have to call my wife first.

　　我得先给老婆打电话。