下列对水的叙述，不正确的一项是（ ）
A．水是生物体中含量最多的物质
B．水可以为人体的生命活动提供能量
C．水在生物体内起到运输物质的作用
D．人体内的大多数生命活动必须在水中完成
答案：B
题目分析：A、生物体中含量最多的物质是水，A正确；
B、食物所含的六类营养物质中，能为人体提供能量的是糖类、脂肪和蛋白质；维生素既不参与构成人体细胞，也不为人体提供能量，水是过程人体细胞的主要成分，但不能为人体的生命活动提供能量，B错误；
C、水在生物体内起到运输物质的作用，C正确；
D、人体内的大多数生命活动必须在水中完成，D正确．
故选：B．
On a trip to California, my family stopped for lunch. As we walked towards the entrance to the restaurant, a man, with a messy beard and _____ hair, jumped up from a bench outside the restaurant and opened the door for us. Paying no attention to his ______, he greeted us in a friendly way. Once inside, my daughters said in a low voice, “Mom, he _______.” After we ordered our lunch, I explained, telling the the kids to look beyond the dirt. We then watched other _____ come into the restaurant but many took no notice of him. Seeing this rudeness truly ______me. The day I became a mother, I had determined to set a good example to my children. Yet sometimes being a good example was _______, especially when things didn’t go right. After our meal arrived, I realized I had left my car-sick pills in the car, so I went back to the car to get them. Just then, the “doorman”was opening the door for a couple. They ______ him without even noticing his presence. Letting them in first, I said a loud “thank you” to ______ as I went out. When I returned, we talked a bit. He said he was not allowed inside _____ he bought food. I went back and asked our waitress to ______ one soup and sandwich. The kids looked puzzed as they had already eaten. But when I told them his story and said the _____ was for the “doorman”, they smiled. When it was time to continue our ______, I found the “doorman” enjoying his meal. Upon seeing me, he stood up and thanked me heartily with tears in his eyes. Back in the car, I fell into deep thought. While we can’t choose many things in life, we can choose _____ to show gratitude. I said thanks to a man who had _____held open a door for me, and also said thanks for that opportunity to teach my children by _______.
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