虚拟语气要用过去时,比如
I wish I had
I wish you could
I wish they would
He wish they did
等等.是固定用法.Have you ever been to Beijing 这里怎么用have，不用had？Have you ever been to Beijing 这个提问不是虚拟，所以不用 had。 只有回答是虚拟。答者是说 “我没去过北京，但我愿望我有去过。”