二、单项填空(本节有10小题,每小题1分,共10分)21. Many people agree that ______ knowledge of English is a must in ______ international trade today.
School children must be taught how to deal with dangerous_________ .
It was foolish of him to _______his note during that important test, and as a result, he got punished.
______hit me suddenly ______ I had forgotten her birthday.
If Joe’s wife won’t go to the party, ________.
It is so cold in Antarctic that the penguins have to stand _______to each other to keep warm.