工程量清单计价方法与定额计价法相比，两种模式的最大差别是( )。

A．主要计价依据及其性质不同
B．编制工程量主体不同
C．单价与报价组成不同
D．体现了我国建设市场发展过程中的不同定价阶段

For safety reasons，when assistance towing（）.

A.the disabled vessel should be towed to the nearest port

B.the disabled vessel should be inspected for flammable gases

C.passengers should always be removed from the disabled vessel

D.personnel on the disabled vessel should don PFD's