1 If the problem keeps up/on happening, we will have to alert the authorities.
2 Who let the dangerous animals away/out of their cages?
3 Sue felt let down/off when she discovered the others had left without her.
4 They carefully picked up/out the safest hiding place.
5 There was a sign warning people to keep away/off the property.
Jagger threatened to resign if the government was defeated.
If the company had agreed, we could have made rapid progress.
The company will refund you if you change your mind.
The exhibition might have closed if they hadn't found new sponsors.
I would refuse to cooperate if I were in your position.
Please inform your doctor immediately if she shows signs of improvement.
Molly and Sali would have realized their mistake if they had only stayed until the end.
You can assume that we agree if you don't hear from us by Sunday.
If you drink too much coffee, you won't be able to sleep.
If John had known about the meeting, he would have come.