The number 911 is special number I think that will be remembered by the Americans for

问题补充：

The number 911 is special number, , I think, that will be remembered by the Americans forever.

A. a, what

B. the ,it

C. a ,which

D. a, one

答案：

A. a, what

B. the ,it

C. a ,which

(答案→)D. a, one

解析：

第一空考查冠词的用法，a special number,“一个特殊的号码”，第二空考代词，one指代a number。选D。句意是：911是个特殊的号码，是美国人应该永远记住的号码。