Young as he is, David has gained ____ rich experience in ____ society.

Since ______ to the world, the dance “GangnamStyle”has caused a release of a certain feeling.

It is said that your grandpa was very brave —Not _________He was _________than brave

—I ________ my son to Laos for sightseeing.—I would rather you didn’t do that，for the bird flu ________ several lives there.[ ]

__________ the reason , research shows that laughteris good for your health.