A good diet and some moderate exercise are ____ to good health. 

 Now that there is much difficulty in finding a satisfying job，why don’t you do a _____ job to support you for the time being?

After the new machine was introduced, the factory produced _____ in 2011 as the year before.

Though my grandfather is in his eighties, he is still as _________ as a young man and hates sitting around doing nothing all day.

. Before radio and TV, music could only be heard _______, that is, you had to go to places where musicians gave performances.