We have made good preparations for Sarah’s birthday, but if she ________ late to the party, it would ruin the surprise for her.
When Mary came, I _____ on the piano.
Cars, buses and bikes ________ stop when the traffic lights turn red.
_______ we got to the station, the train had left already.
Tom kept quiet about the accident _____ lose his job.
He is very old, ______ he still works very hard.