20．No one is sure whom the dictionary ________.　　　　　

A．belonging to　 　B．belongs to　　　　　　　　　　　　　　 C．is belonged to　 D．is belonging to

19．For some time now, Chinese people, under the leadership of CPC，________ the contents of the Scientific Development Theory in the course of practicing socialism in China.

A．had been improving　　　　　　　　　　　　　　　　　　　　　 B．have been improving

C．were improving　　　　　　　　　　　　　　　　　　　　　　　　 D. improved

18．-She speaks German well because she stayed in Germany.

-Really? How long ________ there？　　　　　　　　　　　

A．does she stay　 B．is she staying　　　　　　　　　　　　 C．has she stayed 　D．did she stay

17．-Do you know our city of Xi’an at all?

-No，not at all.You see，this is the first time I ________ here.

A．came　 　　　　　 B．am coming　　　　　　　　　　　　　　 C．was　 　　　　　　　 　D．have been