How kind you are! You always do what you can ____________ others.
Go _____the street, and you can see a park by the river.
Can you describe the people and the things ______ have been seen in Tibet?
Now it’s nearly half past six, and we have a little time ______ to catch the last bus.
I heard from my pen pal yesterday, but I haven’t replied ______ her.
Did you know ______?