With his son ____, the old man felt unhappy.

Nowadays, scientists are working hard to find a best way of treating addictions __________ drugs

ronger the ______ is, the more quicklya person will learn a foreign language That is to say, it is up to whether hehas an interest in the foreign language

Many students believe the choice of their courses and universities should _______ their own interest. [ ]

I’m not sure exactly how much money you’ll receive, but it will________cover your major expenses[ ]