Using 'it' as a dummy subject: It's raining, It seems that
It + be/seem/appear + complement/clause
It isn't easy to learn. It doesn't seem right.
Is it raining? What time is it?
💡 'It' is a dummy/empty subject when there's no real subject. Required in English—can't omit it.
✓It's important to be on time.
✗Is important to be on time.
English requires a subject—use 'it' as dummy subject.
✓It takes two hours to get there.
✗Takes two hours to get there.
Need 'it' as subject even when meaning is impersonal.
✓It seems that she's unhappy.
✗Seems that she's unhappy.
'It' introduces the that-clause.