Question

【题目】我想要知道的是谁解决了这个问题。
I want to know is .

Answer 1

【答案】What；who solved the problem
【解析】what引导主语从句，从句中作宾语，is后接表语从句，who“谁”引导表语从，从句中作主语。故填(1). What (2). who solved the problem。