题干
______ exceptionally heavily might railway services be temporarily dislocated (扰乱).
A：If only it snowed
B：Only in case it snow
C：Only were it to snow
D：Only when snow
答案(点此获取答案解析）
C
，集合
和
的关系的韦恩（Venn）图如图所示，则阴影部分所示的集合的元素共有（ ）