He explained the question again to make it easier .A. to understandB. understandingC. unde

问题补充：

He explained the question again to make it easier .

A. to understand

B. understanding

C. understood

D. understand

答案：

(答案→)A. to understand

B. understanding

C. understood

D. understand

解析：考查句型：make it+adj+to do…，使得做…如何…,it是形式宾语，不定式是真正的宾语，句意：他再次解释这个问题使它变得更容易。选A。