对于一些孩子来说，在学习英语的过程中，最难的就是复杂的时态问题和一些语法变化规则，到底什么时候用he，什么时候用his，在树上是“on the tree”还是“in the tree”呢？下面小编整理了一些关于小学生的英语语法知识，供孩子在学习过程中参考！
一般过去时 should( would) +动词原形
例句 If they were here， they would help you.
过去完成时 should(would) have+ 过去分词
If she had worked harder， she would have succeeded.
The rice would not have been burnt if you had been more careful.
If my lawyer had been here last Saturday， he would have prevented me from going.
If he had come yesterday， I should / would have told him about it.
含义：He did not come yesterday， so I did not tell him about it.
If he had not been ill and missed many classes， he would have made greater progress.
含义： He was ill and missed many lessons， so he did not make greater progress.
一般过去时 should+ 动词原形
were+ 不定式 would + 动词原形
例句 should succeed，were to succeed， everything would be all right