The medicine works more effectively ______ you drink some hot water after taking it.
I went to the airport ___ my brother off.
.I’m sorry, but we don't have ___ English papers.
People on ___ banks of the river are expecting a good harvest in autumn.
Last Sunday when I was walking along the street, I caught ___ of a tall man with a pair of glasses.
They stood under a tree to ___ getting wet.