单选题
Britain might still be part of France if it weren't ______ a disastrous flood 200000 years ago, according to scientists from Imperial College in London.
【正确答案】
D
【答案解析】本题考点为介词的上下文语义。短语if it weren't for常用于虚拟语气，意为“要不是……的话”，其他选项都不能够形成通顺的上下文搭配。根据题意，选项D为正确答案。