The number 5.12 is a special number I think that will be remembered by Chinese people f

问题补充：

The number 5.12 is a special number, ,I think, that will be remembered by Chinese people forever.

A. what

B. it

C. which

D. one

答案：

A. what

B. it

C. which

(答案→)D. one

解析：考查代词：5.12是我认为的一个特殊的数字， 应该被记住的数字。I think是插入语，先可以不看，从而看出有that引导定语从句，不能用which，也不是名词性从句，不能用what，这里需要代词，指代a special number，而且是同位关系，one可以泛指“可数名词单数”，it是特指同类同物，选D。