As the world’s population continues to grow，the ________ of food becomes more and more of a concern.                                                        (2013·浙江，4)

Unlike a stage actor, a film actor must be able to perform small scenes out of ________ and often days apart in time.

Can you believe that in     a rich country there should be      many poor people？

All those second-hand goods are sold at                  before．

I can’t say which wine is best—it’s a _______of personal taste.