问题
选择题
We were all doing our history paper in the classroom yesterday evening________the light went out.[ ]
A. since
B. before
C. while
D. when
答案
答案：D
搜题请搜索小程序“爱下问搜题”
We were all doing our history paper in the classroom yesterday evening________the light went out.[ ]
A. since
B. before
C. while
D. when
答案：D