问题补充：
It is reported that two schools, are being built in my hometown, will open next year.
A. they both
B. which both
C. both of them
D. both of which
答案：
A. they both
B. which both
C. both of them
(答案→)D. both of which
解析：考查定语从句：句意：据报道，在我的家乡正在建的两所学校将于明年启用。both of which引导非限制性定语从句，which指代先行词schools，作of的宾语。they both和both of them都不能引导定语从句，所以是错误的。which both中的which不能修饰both，选D。.
