下面的选项哪个是正确的up__de 提升;升级 A: gra B: gre C: grea D: gree

中国大学MOOC:"Task 2 Fill in each blank with the proper form of the words or phrases given below to complete the following passage. exportprofitprocesstrade specializeconsumeexchangeopportunityparticipation better off We (21) when we spend money in a store, restaurant or any other place of business as a (22) . It is believed that people trade in an attempt to be (23) . The (24) of importing and (25) creates a grea