This river has changed its course many times. It ___ always loca

This river has changed its course many times. It ___ always located where it ___ at present.
A、isn’t; is
B、isn’t; will be
C、wasn’t; is
D、wasn’t; has been
【正确答案】：C
【题目解析】：这条河已经多次改道。它并不总是坐落的地方。