It is (high) time后接简单过去式，表示早该是...的时候了。

It is (high) time that I left.

我早该走了。

在假设语气结构里有时可以省略副词子句，条件一般暗含在片语或上下文里。

Alone by myself, I wouldn't have been delighted.

如果我单独一个人我是不会感到愉快的。

假设语气中的副词子句可以省略连接词if，此子句中的助动词had, were, should等要移至主语之前。

Were I Jane, I would be very pleased to marry you.

如果我是珍,我会很高兴嫁给你。

would that相当于how I wish。

Would that Jane accepted my proposal.

珍要是接受我的求婚就好了。

Even if...表示即使...也。

Even if you failed again, you shouldn＇t give up.

即使你再次失败，你也不应放弃。

may+原形动词是假设语气的一种形式，表示祝愿。

May you succeed!