He ______ sleep, although he tried to, when he got on such a hunt for an idea until he had caught it.

—Why didn’t you come to my birthday party last night? —I planned to, but my parents simply 　　　   not let me out so late at night.

It has been announced that students _______ remain in their seats until all the papers have been collected.

 — Listen! Is that Linda singing in the next room?— No, it ________ be her. She is still in Shanghai.

According to the new traffic laws, people ______ drive after drinking wine or beer.