I am going to Tian’anmen Square to watch the raising of the national flag with Lin Tao it

问题补充：

I am going to Tian’anmen Square to watch the raising of the national flag with Lin Tao it rains early tomorrow morning.

A. if

B. unless

C. when

D. since

答案：

A. if

(答案→)B. unless

C. when

D. since

解析：句意：。我要与林涛去天安门广场观看升国旗，除非明天清晨下雨。If如果；unless除非；when当……的时候；since自从。所以选B。