True Stories B1+ Lesson 31 cause and effect conditionals
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.