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.
You didn't know how unpopular Jason was when you invited him to your party.
If I'd/I had known how unpopular Jason was, I wouldn't have invited him (to my party).
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.
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.
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.
The baby didn't cry, so we had a good sleep.
If the baby had cried, we wouldn't have had a good sleep.
I haven't got a key, so I can't get in
If I had a key, I could get in.
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.
You may want a chat, so just give me a ring.
If you want a chat, just give me a ring.
I'm afraid of spider. I can't pick it up.
If I wasn't/weren't afraid of spiders, I would pick it up.
Throw a stone into water and it sinks.
If you throw a stone into water, it sinks, OR it'll/it will sink.
He's very ill so he isn't at work.
If he wasn't/werent very ill, he would be at work. OR Unless he was very ill, he would be at work.
It won't rain tomorrow and I'll go to the coast.
I’ll go to the coast tomorrow unless it rains. OR I’ll go to the coast tomorrow if it doesn't rain.
