All of Manhattan, parts of Brooklyn and Queens are blacked out, and people have no idea it’s ing back on.
A. that
B. when
C. how
D. where
网友回答
A. that
(答案→)B. when
C. how
D. where
解析：四个选项分别表示定语从句，时间状语从句，方式状语从句和地点状语从句。整句话大概意思是：在整个曼哈顿岛上，布鲁克林和皇后区的部分地区被封闭了，人们不知道何时（WHEN）恐怖分子会再次来袭。故选B。