After a few expressions, English uses a past form to talk about now or the future. Here the past does not mean past time: it shows that the situation is not real, or not real yet. The same idea works after "wish" and "if only".
1. It's time + subject + past
Something should already be happening, and it isn't.
- It's late. It's time we left. (not "It's time we will leave")
- It's high time you found a job.
- It's about time they fixed the lift.
It's time to + verb is also correct, and more neutral: It's time to leave. "High time" and "about time" add criticism: it should have happened before.
2. Would rather
- About yourself → would rather + verb: I'd rather stay at home tonight. (not "I'd rather to stay")
- About someone else → would rather + subject + past: I'd rather you stayed at home.
- Negative: I'd rather you didn't tell her. (not "I'd rather you don't tell her")
- About the past → past perfect: I'd rather you had told me earlier.
3. As if / as though
- Not true → past: He talks as if he knew everything. (he doesn't)
- She treats me as though I were a child. ("was" is common in speech)
- Earlier than the main verb → past perfect: He looked as if he had seen a ghost.
- Probably true → present: It looks as if it is going to rain.
4. Common mistakes
- ❌ I'd rather you don't smoke here.
- ✅ I'd rather you didn't smoke here.
- ❌ It's time we will go home.
- ✅ It's time we went home.
- ❌ I'd rather to walk.
- ✅ I'd rather walk.
