The doctor suggests that I should sleep with the window open ( )it’s very cold.

问题描述:

The doctor suggests that I should sleep with the window open ( )it’s very cold.
The doctor suggests that I should sleep with the window open ( )it’s
very cold.
A. if
B. unless
C. when
D. since

B 除非!
医生建议我睡觉时开着窗户,除非是特别冷. (即:除非特别冷,关着窗户睡,其它时都开着)
A 如果,
C:当
D:既然, 自.开始
只能是B