It as empty subject: It's raining. It seems that... It's important to...
It + be + adjective/noun + to-infinitive/that-clause
It + isn't + adjective + to/that...
Is it + adjective + to/that...?
💡 It doesn't refer to anything specific; it's a grammatical placeholder.
✓It's important to be on time.
✗Is important to be on time.
Need 'it' as subject.
✓It seems that she's upset.
✗Seems that she's upset.
It as dummy subject.
✓It takes two hours to get there.
✗Takes two hours to get there.
It for duration/distance.