Senior 3 high school students should be given enough sleeping time, ____________ they are busy preparing for exams to enter college.
Scientists have shown that there is a connection ____ cigarette smoking and certain diseases.
Most of the universities in China provided scholarships for students ______ financial aid.
In the experiment the scientist kept a watchful eye________the developments and recorded every detail.
He has some trouble ______ his classmates, but he has no trouble ______ doing his lessons.
I bargained with the shopkeeper for a long time, and finally we agreed________the price.