涉及状语从句的几种特定时态1. “”原则即若主句为，时间和条件状语从句通常要用一般现在时表示将来，而不能直接使用将来时态。如：Ill give her the telex when she comes. 她来时把电传交给她。Ill return the book as soon as I have read it. 这书一看完我就送还。Hell have four years at university after he leaves school. 他中学毕业后要上四年大学。2. since与完成时since 引导时间状语从句时，其主句通常要用，有时也用现在完成进行时。如：She has had another baby since I saw her last. 从上次我见到她以来，她又生了一个孩子。He has grown an inch since I saw him. 我上次见到他以后他已长高了一英寸。注：当主句为“It + be + 一段时间”时，则通常用一般现在时代替现在完成时。如：Its more than th
