The weather that day may not be as good as expected in case we will have to put off the

问题补充：

The weather that day may not be as good as expected, in case we will have to put off the event.

A. what

B. that

C. this

D. which

答案：

A. what

B. that

C. this

(答案→)D. which

解析：考察定语从句关系代词的用法。Which在本句中作定语修饰case，in which case指在那种情况下。句意：那一天的天气也许不像预料的那么好，在这种情况下，我们将推迟这项活动。