句意：他一到就会立刻打电话给你。本题考查的是as soon as引导时间状语从句的用法。as soon as一般有两种情况：(1)指未发生的动作，主句用一般将来时，从句用一般现在时代替一般将来时，例：1 will tell him the news as soon as he comes back．(2)指紧接着发生的两个短动作，主从旬都用一般过去时，例：He took out his English books as soon as he sat down．A为现在进行时，B为一般将来时，故选C。【知识拓展】时间状语从句的引导词：(1)when当…时候，通常指某一特定的时间点，主句与从句的动作同时发生。例：When I opened the window，I saw him come up．我打开窗户时看见他走上前来。(2)while在…期间，往往指一段时间。例：Don’t phone me while I’m at the office．我在办公室时，别打电话给我。(3)before在…之前。例：Did you work as a stewardess before you come to this company?来这个公司之前你是当空乘的么?(4)after在…之后。例：I arrived there after she left．我在她离开之后才到达那儿。(5)since自从…，通常主句用现在完成时。例：I’ve been doing this work since I retired．退休后我一直在做这工作。