Question

高一英语单选题

单选题：At Tsinghua, for example, freshmen need to register and find their dormitory by themselves. The process requires two to three hours, _____________ volunteers take parents on a tour of the campus.
A.during which B.during that C.during that D.during what 麻烦说明正确答案的原因,语法角度。感觉A和B都行吧？

Answer 1

选择A 这是非限定性定语从句，which指代上文，during是介词，介词后不能用that，只能用which