Question

【题目】He was so deep in thought，thinking of the problem ________ he knocked into the tree without noticing it.

A．when

B．while

C．because

D．that

Answer 1

【答案】D

【解析】考查状语从句的引导词。so...that...表示“如此……以致……”，引导结果状语从句。句意为：他思考问题太投入了，以致一不留神儿撞到了树上。D为正确答案。