The rain is very heavy we have to stay at home.A. but B. becauseC. so

问题补充：

The rain is very heavy we have to stay at home.

A. but B. becauseC. so

答案：

解析：考查连词用法辨析。but表示转折；because引导的状语从句表示造成结果的原因。so引导的状语从句表示原因产生的结果。句意：雨下得很大，因此我们必须呆在家。