1) If you drop an apple, it falls.
2) I get tired if I work too much.
3) Water boils if you heat it to 100° C.
4) I will phone my friend if I have time today.
5) If you freeze water, it turns into ice.
6) If it rains today, I will stay at home.
7) If I see you tomorrow, I will buy you a drink.
8) We will go to the beach if it is warm tomorrow.