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 don't know Jason and you don't invite him to your parties.
If I knew Jason, I would invite him to my parties.
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.
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.
Critizise your friend. She should start preparing her projects earlier. She will probably be so far behind now.
If you started preparing your projects earlier, you wouldn't be so far behind now.
Your friend might need some help. If so, tell her to give you a call.
If you need some/any help, give me a call.
The automatic result of the door opening is the fan coming on.
If the door opens, the fan comes on.
I haven't got a key, so I can't get in.
If I had a key, I could get in.
You will talk about football and I'm sure I will to be very bored.
If you talk about football, I'm sure I will be very bored.
The baby doesn't cry at night, so we have a good sleep.
If the baby cried at night, we wouldn't have a good sleep.
You may want a chat, so just call me.
If you want a chat, just call me.
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 go away and I'll miss you.
If you go away, I'll miss you.
I'm not rich or I'd have given up working long ago.
If I was/were rich, I'd/ would have given up working long ago.
I'm afraid of spiders or I'd have picked it up. Use UNLESS
Unless I was/were afraid of spiders, I would have picked it up.
Throw a stone into water and it sinks.
If you throw a stone into water, it sinks.
