it is time to do something

It is time to/for …
a time when something should happen
It is time to DO sth
1. It is time to say goodbye
2. I think it’s time to let you know.
3. I suppose It’s time to improve your English.
It is time FOR sb to DO sth
It is time FOR sth
1. It’s time for breakfast/lunch/dinner.
2. It’s time for you to change your bad habits.
3. It’s time for us to relax.