例句是If引导的条件状语从句吗?If引导的条件状语从句的时态是怎样的?这些句子是初二书上的, If you want to tunrn on the recorder,press the blue button. If you like great music ,please welcome Sally Maxwell! If the red right doesn't come on ,wait for thrity seconds. If there's no green light .choose the "copy" symbol.