Your friend might need some help. If so, tell her to give you a ring.
If you need some/any help, give me a ring.
I'm not rich so I have to work.
If I was/were rich, I wouldn't (have to) work.
We're lost because I don't have GPS on my phone.
We wouldn't be lost if I had GPS on my phone.
You may want a chat, so just give me a ring.
If you want a chat, just give me a ring.
I'd really like this vase, but I don't have enough money.
If I had enough money, I would buy that vase.
You think Emma should book a seat on the train. Otherwise, she has to stand.
If Emma doesn't book a seat on the train, she'll have to stand.
I haven't got a key, so I can't get in.
If I had a key, I could get in.
He's very ill so he isn't at work.
If he wasn't very sick, he would be at work.
The automatic result of the door opening is the fan coming on.
If the door opens, the fan comes on.
You talk about football and I'm going to be very bored.
If you talk about football, I'm going to be very bored.
I'm afraid of spiders and I can't pick it up.
If I wasn't afraid of spiders, I would pick it up.
The baby is quiet, so we can sleep.
If the baby cried, we wouldn't be able to sleep.
Warn your friend not to put too many tins into the plastic bag or it'll break.
If you put too many tins into the plastic bag, it'll break.
I am really stressed out about work. Now, I can't have fun at this party.
If I wasn't so stressed out about work, I would have fun at this party.
Nigel hasn't got satellite TV, so he can't watch the game.
If Nigel had satellite TV, he could watch/would be able to watch the game.
I am late with my project because I always procrastinate.
If I didn't always procrastinate, I wouldn't be late with my project.
Throw a stone into water and it sinks.
If you throw a stone into water, it sinks, OR it'll/it will sink.
It won't rain tomorrow and I'll go to the coast.
We’ll go to the coast tomorrow if it doesn't rain.
You are thinking of going away. I will miss you.
If you go away, I'll miss you.
You haven't got a pen, so you can't write down the address.
If I had a pen, I could write down the address.