【观察】观察下列几组句子中虚拟语气的用法，然后加以总结。
1. a. Mr. Li suggested that we (should) put off the sports meeting till next month.
b. It is required that all of us (should) be present at the meeting.
c. The doctor’s suggestion is that I (should) stay in bed for another three days.
2. a. John wants to see me today, but I would rather he came tomorrow.
b. Now I regret going to the cinema with him. I would rather I had stayed at home.
3. a. It is high time that we took measures to protect these endangered animals.
b. It is time that you made up your mind.
