They would have gone for a walk
She wouldn't have come by train
Past perfect
If they hadn't eaten so much
If I were him,
past simple
If I didn't have this homework to do,
You wouldn't be so tired
I would have gone out with my friends
if it wasn't raining
if you'd gone to bed earlier
if she could drive
would/ wouldn't have+infinitive
they wouldn't feel ill now
I wouldn't have quit my job until I'd found another
Would/wouldn't