Pinching of the cargo hose between the vessel and the dock should be prevented by（）.

A.adjusting the hose supports

B.laying out an excess length of hose on deck

C.tying off the topping lifts and runners to winch heads

D.All of the above

建国60年来，改革开放后三十年比前三十年发达很多的原因在于（）。

A.社会的进步

B.科学的发展

C.引入了市场机制

D.法律更加完善