考点四 虚拟语气
技巧点拨
虚拟语气历来是英语学习中的一个难点，尤其是它还有一些特殊形式和用法，是博士研究生入学考试的常考项目，在完形填空中，经常会出现。虚拟语气的基本构成和解题技巧在词汇结构一周已讲解，这里不再赘述。
典型真题
例1：
The discovery has stunned scientists，who 28 that around 50bn tons of meltwaterwere being shed each year and not being replaced by new snowfall.（北京大学2012年）
28.A.believed B.had believed C.have believed D.were believing
【名师点评】B。本句的句意为：这一发现震惊了科学家，与科学家以前的看法不同，所以用过去完成时，had believed意为“以前一直认为……”。故答案为B。
例2：
The experienced driver looked over the engine carefully lest it____on the way.（南京师范大学2015年）
A.goes wrong B.would go wrong C.went wrong D.go wrong
【名师点评】D。lest一般跟should do的虚拟结构，should可以省略，故答案为D。句意为：这位经验丰富的司机仔细地检查了发动机以防车在路上抛锚。
实战演练(https://www.daowen.com)
1.A magazine has pointed out that headache pills without sold name can be sold very cheaply，but the same pills，if advertised____a cost of half a million pounds a year，cost five times competition.
A.they were B.it was C.there was D.there were
2.There is a general understanding among the members of the Board of Directors that chief attention____to the undertaking that is expected to bring the highest profit.
A.is given B.gives C.should be given D.must be given
3.Had the little Scotch lad，Ferguson，allowed the busy brain to go to sleep while he tended sheep on the hillside，instead of calculating the position of the stars by a string of beads，he____become a famous astronomer.
A.would never have B.had never
C.have never D.would have never
答案解析
1.D。虚拟语气。根据题意，这里应是一个there be的结构，由于if引导的从句是虚拟语气，所以答案是D。
2.C。虚拟语气。understanding如同suggestion，motion，plan，idea，order等词一样，其后同位语从句中的谓语动词须用虚拟语气，should加动词原形或直接用动词原形。句意为：董事会的成员一致认为主要的精力应该放在为取得最高利润而做的努力上面。
3.A。虚拟语气。had sb.done sth.意为“……坏事”，为虚拟语气结构；sb.would never have done sth.意为“……好事”。