提问月份用什么特殊疑问词

提问月份有两种情况。如果月份前面有介词我们通常使用when提问。如：They went to China in February. 如果要对in February提问则是：When did they go to China?

如果月份前面没有介词则使用which month提问。如：July is usually the hottest month in a year. 对July提问则是：Which month is usually the hottest month in a year?

对于月份提问的特殊疑问词是when或者Which month。