1. don't
If you're tired, why don't you go to sleep? "Because if I go to sleep now I will wake up too early."
If you don't want to put on sunscreen, that's your problem. Just don't come complaining to me when you get a sunburn.
Don't ramble.
Worrying is like paying a debt you don't owe.
A drunkard is somebody you don't like and who drinks as much as you do.
Don't feel so bad. There's always someone worse off than you.
I don't understand and I'm not used to not understanding. Please explain it once more.
If you don't start treating people with a little more respect, people may start avoiding you like the plague.
Why don't we just reformat the hard disk? You've been having a lot of trouble with it.
If you are a parent, don't allow yourself to set your heart on any particular line of work for your children.
Don't worry. It's a common mistake.
If you hear hoofbeats, don't look for zebras.
Do you think it's worthwhile? I don't think so.
I don't know if it will be fine tomorrow, but if it is fine we'll go on a picnic.
If I don't fail, I will get my driving license before New Year.