such a person.

　　答案：couldn't　couldn't表示对过去的否定推测。

　　3. It was my fault. I ________ (tell) you about the meeting earlier.

　　答案：should have told　表示"本应该做但没有做"，用should have done。

　　4.-Can I pay the bill by check?

　　-Sorry, sir. But it is the management rule of our hotel that payment ________ be made in cash.

　　答案：shall　shall与第二、三人称连用，表示规则，允诺或具有法律效力的事。

　　5. I couldn't ________ (go) through that bitter period without your generous help.

　　答案：have gone　表示对过去情况的虚拟，应用情态动词＋完成式。

　　6. I can't leave. She told me that I ________ stay here until she comes back.

　　答案：must　"must"必须，符合句意。

　　7. ________ (persuade) him not to do so, he wouldn't have made such a serious mistake.

答案：Had I persuaded　句意：要是我事先说服他不那么做的话，他就不会犯这么严重的错误了。题干中主句的谓语部分为wouldn't have made，表示该动作与过去事实相反，故条件句用had