1) If I know, I will tell you. / If I knew, I would tell you.
2) If she wants to talk, she will ring up. / If she wanted to talk, she would ring up.
3) Her health will improve if she sleeps longer. /Her health would improve if she slept longer.
4. If he has enough money, he will buy a large house. / If he had enough money, he would buy a large house.
5.She will feel lonely if Peter goes out every evening. / She would feel lonely if Peter went out every evening.
6.We will be pleased to see you if you arrive. / We would be pleased to see you if you arrived. 
7.If we can come on Sunday, we will come. / If we could come on Sunday, we would come.
8.I will understand Mr. Smith if he speaks slowly. / I would understand Mr. Smith if he spoke slowly.
9.We wont go by ship unless there is no other way. / We wouldnt go by ship unless there was no other way.
10.If you dont give him good meals, he wont  be able to work hard. / If you didnt give him good meals, he wouldnt be able to work hard.