问题补充:
Many people agree that___knowledge of English is a must in___international trade today.
A. a;/
B. the; an
C. the; the
D. /; the
答案:
(答案→)A. a;/
B. the; an
C. the; the
D. /; the
解析:此处knowledge 表示“知道;熟悉”,是know的名词形式,常与不定冠词连用。trade 指“某种贸易”,通常不与冠词连用。