国家竞争力的核心是( )。
A.经济能力B.外交能力C.自主创新能力D.社会管理能力
参考答案:C
— No, I'm afraid he isn't in. This is his secretary speaking. Can I help you?
— _____.[ ]
A. Oh, you will.
B. Oh, that's a pity.
C. I should think so.
D. Well, I look forward to hearing from you.
食管穿孔的影像学征象包括()。
A.尖刺状突
B.龛影形成
C.管扭曲成角
D.憩室样变
E.纵隔炎