—Can I pay the bill by check?—Sorry,sir.But it is the management rules of our hotel that payment ____ be made in cash.

In order to do something meaningful, it’s necessary that you _______ determine what is really important.

Had it not been for the haze（霾）weather phenomenon, there         fewer car accidents in Beijing then．

He _____ have finished his work; otherwise, he wouldn’t be enjoying himself by the seaside.

—George, ___   _ you sing so loudly at such a late hour? —I am terribly sorry．