Use 'unless'
If he isn't ill, he'll come to see us at the weekend.
He will come to see us at the weekend unless he is ill.
If they ___________ (come), I ____ (be) really surprised.
If they come, I will be really surprised.
When you _________ (arrive) , we _________ (go) to the cinema together.
When you arrive , we will go to the cinema together.
Please, call me __________ you are back.
Same points for another team.
Please, call me when you are back.
you /get back late/ I / be / angry
If you get back late, I will be angry.
She won't go to the university if she doesn't study more.
Less points for another team.
She won't go to the university unless she studies more.
If it ________(rain), we ________________ (not/go) to the beach.
If it rains, we won't go to the beach.
She _________ (not help) until we ________ (ask) her to do it.
She won't help) until we ask her to do it.
There could be a letter from Bill today. ___________ there is, please tell me.
There could be a letter from Bill today. If there is, please tell me.
Susan / eat / too many sweets / she / get / fat
If Susan eats too many sweets, she will get fat.
If we don't hurry, we won't get there on time.
We won't get there on time unless we hurry.
You ___________ (regret) it if you ______(eat) all that cake.
Double points
You will regret it if you eat all that cake.
I _________ (go) for a walk as soon as it _______ (get) warmer.
I will go for a walk as soon as it gets warmer.
I'm going to town tomorrow. ____________ you need anything, phone me.
I'm going to town tomorrow. If you need anything, phone me.
The weather / be / as sunny tomorrow as it was today / we /go / surfing
If the weather is as sunny tomorrow as it was today, we will go surfing.