The taxi base fare(起步价) in Hangzhou _____ from 10yuan to 11yuan last month.

   A .raised      B .was raised       C .has raised        D .has been raised

Those scientists ______ a base at the South Pole last year.

[　　]

A. set upon　　B. set out　　C. set up　　D. set down

This story ________ a real event in history.

A. base in

B. base on

C. is based in

D. is based on