由连词if引导构成的条件状语从句分真实性条件句和非真实性条件句两种。高考从以下四个方面对其考查.兹分述如下。热点一、从属连词的选择引导条件句的从属连词if表示“正面”条件.而unless表示“反面”条件,as long as表示“唯一”条件。unless可以和if..not互换。【例1】She says that she’ll have t0 close the shop____business improves.(2013年江西卷)A.if B.unless C.after D.when解析:选B。句意:她说她不得不将这家商店关闭.除非生意有起色。前后存在条件关系,且为反面条件,故选择 Conditional adverbial guidance formed by the conditional adverbial clause sub-conditions of authenticity and non-truth conditional two. The college entrance examination from the following four aspects of its test. Hot one, the choice of subordinate conjunctions Guidance conditional subordinate conjunction if said “positive ” condition, while unless said “negative ” condition, as long as said “only ” condition. unless can be interchangeable with if..not. 【例 1】 She says that she’ll have t0 close the shop____business improves. (2013 年 江西 卷) A.if B.unless C.after D.when Sentence meaning: She said she had to shut down the store unless the business has improved. There are conditions before and after the relationship, and the negative conditions, so the choice