A．flexible.
B．unworkable.
C．the best way.
D．effective.
参考答案B
解析:
你可能喜欢
A．2,012 kilometers.
B．2,020 kilometers.
C．1,200 kilometers.
D．1,300 kilometers.
A．Russia has the biggest natural gas reserves in the world.
B．The European Union buys 30 percent of its gas and 25 percent of its oil from Russia.
C．Russia is the world's second-largest oil producer.
D．The European Union estimates that by 2020, three-quarters of its natural gas will be imported.
