Question

(2013·江西南昌一模)It hasn't been made clear ________ the new underground line is to be open to traffic.

A．when B．that

C．what D．where

 

Answer 1

A

【解析】选A　考查名词性从句。句意：新的地铁线路何时开放还不清楚。句中it是形式主语，空处引导的是主语从句。根据句意可知选when。