She studies ___ medicine before she turned ___ writer.
There is a common belief among them _______ rubbish can and should be put into good use.
We never doubt ______ our school team will win the match against No. 3 Middle School.
The teacher usually grades the students on _______ they have behaved.
Once _____, it won’t be easily forgotten.
_______ David says sound right to Helen. That’s why he has made up her mind to leave the matter to him _______ happens.