He began to take political science_____ only when he left school. 

In the good care of the nurse, the boy is       recovering from his heart operation.

I’m in a hurry. You’d better tell me the truth _______.

The national parks are very important for the protection of these wild animals, which would ______ run the risk of becoming extinct.

She sells second-hand articles at reasonably fair prices from 10 to 50 dollars ____ in her shop.