It is reported that the underground system in Changsha now will be open in 2015.
A. is being built
B. built
C. being built
D. is built
网友回答
A. is being built
B. built
(答案→)C. being built
D. is built
解析：考查非谓语动词。句中being built in Changsha now现在在长沙被建，在句中作定语，修饰the underground system，故选C。