On July 20 1969 Neil Armstrong become the first man foot on the moon .A. settingB. setC.

问题补充：

On July 20, 1969, Neil Armstrong become the first man foot on the moon .

A. setting

B. set

C. to setting

D. to set

答案：

A. setting

B. set

C. to setting

(答案→)D. to set

解析：考查不定式做定语。当名词是序数词或者有序数词修饰的时候，用不定式做定语对其进行修饰。The first man to set foot on the moon指第一个登上月球的人。