下列哪项有关尿含铁血黄素试验的说法，正确的是（）

A.是慢性血管内溶血的有力证据

B.含铁血黄素内主要为二价铁

C.急性溶血者尿中始终为阴性

D.经肝细胞分解为含铁血黄素

E.阴性时能排除血管内溶血

A shepherd’s crook is used to（）.

A.lower spring buoys into the water

B.find an anchor after the buoy has been lost

C.transfer a pennant wire to the anchor handling boat

D.clean chain as it is hauled into the rig