第Ⅰ卷 (共115分)
第二部分 英语知识运用(共两节,满分45分)
第一节 单项填空(共15小题;每小题1分,满分15分)
从A、B、C、D四个选项中,选出可以填入空白处的最佳选项,并在答题卡上将该项涂黑。
21.As________birthplace of Huaxia civilization,Xi' an is________city with a long history and abundant cultural relics.
A. the;a B. a;a C./;a D. the;/
22.H7N9 control and prevention is a________to China as well as the whole world.
A.surprise B.challenge C.reaction D.threat