the three questions which one is the most difficult to answer?A. AsB. InC. ThanD. Of

问题补充：

the three questions, which one is the most difficult to answer?

A. As

B. In

C. Than

D. Of

答案：

A. As

B. In

C. Than

(答案→)D. Of

解析：As如同，当做；In在里面；Than比；Of属于，……的。句意：在这三个问题中，哪个是最难回答的？结合语境可知选D。