方药配伍中寓“清金治木”之义的是A．桑菊饮B．泻白散C．凉隔散D．羚角钩藤汤E．镇肝

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

请写出一个次数为2，系数为－1的单项式             .

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教学中学生直接经验的获得与人类实践活动中直接经验的获得方式相同。

如图所示，一两端开口的塑料软管，用橡皮膜将下端开口扎紧（密封），将塑料软管竖直放置时，从上端开口处倒人一定量的水，可以发现橡皮膜向下凸起（图甲），此时若将软管下部某处按图乙所示适当弯曲（图中橡皮膜未画出），你认为橡皮膜凸起的程度与图甲相比是变大、变小还是不变?利用所学的物理知识说明你判断的理由。