克山病是一种以（）为主要病理改变的地方病，因此，此病亦称为（）.

When evacuating a seaman by helicopter lift，which statement is TRUE?（）

A.Evacuation should be from an area forward of the bridge

B.The vessel should be slowed to bare steerageway

C.If the hoist is at the stern，booms extending aft at the stern should be cradled with the topping lifts hove taut

D.The litter should not be touched until it has been grounded