题目

下列各项，有利于世界多极化趋势的是（ ）①欧共体的形成 ②中国国际地位大大提高③不结盟运动的兴起④日本成为经济大国 A . ①②③ B . ②③④ C . ①③④ D . ①②③④ 答案：DIt's good for you to keep ________ when you have difficulty _________. [     ]A. trying; to do it B. doing; to do it C. to try; to do D. trying; doing it