a. First type

To pass your driving test you will have to practise quite a lot

If you practise quite a lot, you will pass your driving test

 

It's time we started packing if we want to take the 10.30 train.

If we want to take the 10.30 train, we should start packing.

 

b. Second type

I haven't much time so I read very little.

If I had more time I would read more.

 

They don't clean the windows so the rooms look rather dark.

If they cleaned the windows, the rooms wouldn't look so dark.

c. Third type

She didn't know you were in hospital, so she didn't visit you.

If she had known you were in hospital, she would have visited you.

 

I didn't see the signal, so I didn't stop.

If I had seen the signal, I would have stopped.

Unless = if not

Unless you kick the ball very hard, it won't reach the goal.

If you don't kick the ball very hard, it won't reach the goal.

 

If you don't dress properly, you won't go to the party with me.

Unless you dress properly, you won't go to the party with me.

 a. I wish + past simple (regret about the present)     

It's a pity they live so far.           

I wish they didn't live so far.

 
b. I wish + past perfect (regret about the past)

It's a pity they left the party so early. It was rather boring afterwards.

I wish they hadn't left the party so early.

 
c. I wish + would + infinitive (complain)

Why do you always drop your cigarette ash on the carpet?

         I wish you wouldn't drop your cigarette ash on the carpet.