______ the flight to New York will be put off is ______ I’m especially worried about.

A．Why; what

B．Whether; what

C．How; that

D．When; that

临床上喉外伤可分为两大类，正确的分类是（）。

A.闭合性喉外伤和开放性喉外伤

B.喉的外部伤和喉的内部伤

C.喉的意外创伤和喉的医源性创伤

D.喉挫伤和喉切割伤

E.喉创伤和喉烧灼伤