---Why do you look so upset?---There are so many troublesome problems _____.
You can find the new hospital ___ the end of the street.
___ the end of this new term we'll have graducated from middle school.
The mid-term exam is to be held ___ the end of this month.
I’ll be free ___ seven o’clock.
We offered him our congratulations ___ his passing the college entrance exams.