Water is (41) important of all the things we (42) and drink. Not many people understand this, (43) it’s quite true. The human body (人体) can go (44) food for a long time, but two (45) three days without water can usually (46) people die.
Many people don’ t understand how much water the human body needs to work well and many people do not drink (47) , even (48) hot weather.
Our body is (49) water, about 65% to 75%, ff we do not have enough water, we’ll (50) tired and many will get ill. So you see, how important water is to us all.

[A] or[B] and[C] in

为保持胸腔闭式引流管能够有效引流，以下说法错误的是（）

A.如果病情允许，取半坐位

B.定期以离心方向挤捏引流管

C.鼓励做深呼吸，咳嗽，但不要变动体位，以防引流管脱出

D.注意观察引流管，防止受压，扭曲，阻塞

E.水封瓶距离引流口平面一定距离