The mixture of his improved self-confidence and never-ending efforts is ________ lies behind his rapid progress in his study.
___ 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.
In the dark street, there wasn’t a single person ___ she could turn for help.