If a country has a lower opportunity cost than its potential trading partner, the country should decide to be self-sufficient.

A．The young courtier put in the trial occupies the central importance.
B．Much of the story is about the princess’ reflections and psychological struggles.
C．The tiger represents violence that destroys justice.
D．Much of the story is about whether the king’s penal system would work.

A.增加进气量
B.增加喷油量
C.增加进气量同时增加喷油量
D.都不对

A．2008
B．2011
C．2009
D．2010