You have to wear a helmet and a life jacket for protection, just ____ you fall into the water.
Supermarkets are supplied with __________ red lucky gifts at the Spring Festival.
I thought my eyes must be playing tricks _______ me.
In the quiet darkness, I could hear someone _______ the door and go upstairs.
Would you mind _______ some questions?
After the party, I found my necklace _____.