It was not until one night_____we were doing our cleaning-up I got curious and wanted to see what was on the top floor.
Postage ______, the necklace will cost you at least 650 yuan.
We all think that _____ no need to make laws to prevent the young from getting married during their college life.
Everyone hopes that we can do something to make things better, so we can't help ______ under the stress.
You ______ be driven out of the school if you dare to cheat in the exam.
On hearing a great noise, Mike looked forward through the window _____ what happened outside the room.