The past two years a sharp rise in oil price which adds to the burden of auto transporta

问题补充：

The past two years a sharp rise in oil price, which adds to the burden of auto transportation industry.

A. witnessed

B. has witnessed

C. is witnessing

D. witnesses

答案：

A. witnessed

(答案→)B. has witnessed

C. is witnessing

D. witnesses

解析：考查时态题。根据the past two years可知应该用现在完成时。本句是无生命的东西作主语，此处的the past two years作主语。witness 解释为：见证了。