We offered him our congratulations ____ his passing the college entrance exams.
---Why don’t we go to the new Sichuan restaurant for a meal? -----_____
-----_____ leave at the end of this month. -------I don’t think you should do that until _____ another job.
He tried his best to solve the problem, _____ difficult it was.
The missing boy was last seen_____ near the East Lake.
Out of ___ for the homeless children he gave them shelter for the night.