Ray is a new graduate, and it seems that he has difficulty in dealing with ________ problems arise.

______ nearly all behavior is learned behavior is a basic assumption ______ has been put forward by the social scientists.

It has been 60 years ______ the two countries established diplomatic ties.

We do not have enough money.________，we cannot afford to buy the new car.

—People often don't appreciate what they have, do they? —No, _________ they lose it.