1. [a]happens [b]happened
[c]should happen [d]had happened
2.[a]check and recheck [b]checking and rechecking
[c]be checked and rechecked [d]checked and rechecked
2.The people who knew him very well said that he was too na?ve sometimes.Had he been older,he___1___less sympathetic.But what he had done proved that he was the person,loving life,also a hero who can help others out of trouble.___2___his timely arrival, the boy would have been drowned.That gained respects for him.
3.[a]might have been [b]would be
[c]might be [d]had been
4.[a]But for [b]Even for
[c]Except for [d]If not
1. 选[c]该题考察表示惊奇、高兴、遗憾、担心等感情色彩的形容词引起的主语从句中的虚拟语气的表达。在 anxious,sorry,concerned,happy,delighted等表示感情色彩的形容词后接的that 从句中，用should来修饰谓语动词。该句中有strange一次，意为“奇怪”，表示对事物的惊讶或不满，it为形式主语，that从句为主语从句，要求从句中用虚拟语气的表达形式should+动词原形表示
2. 选[c]该题考察it’s+adj.+that主语从句的虚拟形式。观察句子结构可以看出这里为It’s+形容词(important)+that从句结构，形容词important做表语，主语从句需要虚拟形式should+动词原形，should可以省略
3. 选[a]该题考察非真实条件的虚拟。在表示过去情况的虚拟条件句中，条件从句用了过去完成时形式，主句可用should(would/could/might)+have+过去分词的形式
4. 选[a]该题考察含蓄条件的虚拟。But for含义为“要不是”，用于此处可以表达假设条件，but for his timely arrival=If it had not been for his timely arrival或If he had not arrived on time.