PSAs are often run _____ free, and are ______ to educate people about health, safety, or any other problem that affects public welfare.
The Parkers bought a new house but ____ will need a lot of work before they can move in.
-Do you like ___ here? -Oh,yes. The air,the weather,the way of life. Everything is so nice.
I like ____ in the autumn when the weather is clear and bright.
It was at four o'clock in the afternoon ____ he and his grandpa reached the museum in Guanghan.
I consider____ my duty to help you.