9.[答案] C　[考点]考查强调句型。 [译文]只有当你即将失去某人时，你才会充分意识到他对你是多么重要。 该句是一个典型的强调句式，It is only when...that...强调的是when引导的时间状语，故C为正确答案。 It is...that...强调句型举例： It was three books that he read in the library yesterday.昨天他在图书馆读了三本书。 Was it ten years ago that his father died?他的父亲是十年前去世的吗? It is at5o'clock that the train will arrive.火车将在五点到。 When is it that you will set off?你到底什么时候出发？