Question

【题目】_______ astonishes us is that AlphaGo defeated the human champion.

A. Which B. When

C. That D. What

Answer 1

【答案】D

【解析】

试题分析：考查主语从句。本句中what引导主语从句并在该主语从句中做状语。that和when是不能在名词性从句中做主语的，which指特定范围之内的某一个。句意：让我惊讶的是AlphaGo击败了人类的冠军。故D正确。