从北朝晚期至中唐时期漫长的岁月里，（）实际上成了中西交通的中心之一。

A.丝绸之路

B.丝绸之路青海道

C.丝绸之路北道

D.丝绸之路西道

While in drydock your vessel will be belt-gauged.This process involves（）.

A.measuring the thickness of the tail shaft liner

B.taking the vessel's offsets to check for hull deformation

C.testing and examining the anchor cables for defective links

D.drilling or sonic-testing the hull to determine the plate thickness