surprised me most was to see so many people waiting for my arrival.A. ThatB. ItC. Which D

问题补充：

surprised me most was to see so many people waiting for my arrival.

A. That

B. It

C. Which

D. What

答案：

A. That

B. It

C. Which

(答案→)D. What

解析：句意：令我最惊讶的是，我看到这么多的人在等我的到来。What引导主语从句在主语从句中作为主语，That亦可引导主语从句，但是不做任何成分，只起到连词的作用，故选D