分类：教育/科学-学习帮助
问题：为什么？1.It'shightimethatallofyou__ 
1.It's high time that all of you _____ a rest.  A. had                    B.have  . should have had        D. must have （这道题应选Ａ。能不能给我解释一下虚拟语气在定语从句中的使用！）２．We ______ last night, but we went to the concert instead.  A. would study        B. might study  C. should have 1.It's high time that all of you _____ a rest.  A. had                    B.have  . should have had        D. must have （这道题应选Ａ。能不能给我解释一下虚拟语气在定语从句中的使用！）２．We ______ last night, but we went to the concert instead.  A. would study        B. might study  C. should have studied（这道题为什么选C而不选B？语句是什么意思？）3. I told his about my telephone number, but most probably I _______.  A. should write it down  B. should have written it down  （为什么选Ｂ而不选Ａ？）4.Where were you this afternoon? I tired to call you.  I ______ to the library for a while.  A. tired go         B. had to go  （为什么不选Ａ？）
回答：1.固定句式：It is high time ......+过去式，该句型表示"该做……的时候了"．
２．虚拟语气，表示本该做而事实上没做，可以从从句中分析语境来选择是否虚拟．
３．表示本该做而事实上没做，碰到这类句子首选虚拟语气．
４．try to do－－－试着做某事
　　had to do------不得不做某事
　　从语意上看Ａ和Ｂ中当然Ｂ比较符合逻辑．