1
1) If you don't feel well, you go to the doctor.
2) If babies are hungry, they cry.
3) If Tom has a birthday party, he usually invites a lot of friends.
4) If I have a headache, my mother gives me some medicine.
2
1) If I go out tonight, I'll go to the cinema.
2) If he comes, I'll be surprised.
3) If the weather doesn't improve, we shan't ( или won't) have a picnic.
4) If you don't want to go out, I'll cook dinner at home.