重症手足口病并发神经源性肺水肿的主要治疗措施是（）

A.用强心剂

B.镇静、吸氧

C.机械通气

D.应用血管活性药物

E.输新鲜冰冻血浆

Each lifeboat must be lowered and maneuvered in the water at least once every（）.

A.2 months

B.3 months

C.4 months

D.5 months