题目

世界上发达国家最集中的区域是（ ） A . 东南亚 B . 撒哈拉以南非洲 C . 西亚 D . 欧洲西部 答案：DIf he ________ busy now, he would have much more time to do exercise.  [     ]A. doesn't B. isn't C. weren't D. won't be