虚拟语气的特殊表现形式

　　一、表示“好像”：除了if条件从句外，由as if和as though等引导的状语从句表示方式时，意思是“好像”,这时从句中的谓语动词应用虚拟语气。其动词形式用过去时(be用were的形式)表示所说的与现在的事实相反；用过去完成时表示所说的与过去的事实相反

　　Violetta has a curious ［A］ expression on ［B］ her face as though she was smiling ［C］ about something that amused her ［D］ .

　　二、特殊连词的需要：lest, for fear that和in case引起的从句(这时谓语多用should＋加动词原形)

　　We dare not play jokes on Mr. Wang lest he should become angry. (我们不敢跟王先生开玩笑，恐怕他生气。)

　　He hurried on, lest he should drop out in the forced match. (他加紧步伐，生怕在急行军中掉队。)

　　Every attention must be paid to him lest he (should) feel that he is inferior to my other guests. (我对他特别关照，唯恐他感觉到比我的其他客人低人一等。)

　　He’s working hard for fear that he should fail in the exam. (他加紧学习唯恐诊断不及格。)

　　三、介词短语表示虚拟：有时假设的情况并不以条件从句表示出来，而是通过一个介词短语来表示，或通过上下文或其他方式表示出来。如 but for, but that…, in case of, otherwise, supposing, under more favourable condition, without 等表示让步假设

　　He worked very hard; otherwise he might have failed. (他刻苦工作，不然他就失败了。)

　　We could have done better under more favorable conditions.(假设我们有更有利条件，我们还会做得更好。)

　　But for his help，I _____ .

　　［A］ should not have succeeded

　　［B］ had not succeeded

　　［C］ did not succeed

　　［D］ have not succeeded