下列哪项是营养性缺铁性贫血的主要原因

A．生长发育加快

B．从食物中摄入的铁不足

C．造血功能增加

D．铁的消耗过多

E．贮存铁耗尽

When jumping into water upon which there is an oil-fire，you should（）.

A.break the water surface with your hands when diving head-first

B.use your hands to hold your knees to your chest

C.cover your eyes with one hand while pinching your nose shut and covering your mouth with the other

D.enter the water at the bow or stern on the windward side of the vessel