质子和中子都是由u夸克和d夸克组成，u夸克带电量为
A．质子由1个u夸克和1个d夸克组成，中子由1个u夸克和2个d夸克组成
B．质子由1个u夸克和2个d夸克组成，中子由2个u夸克和1个d夸克组成
C．质子由2个u夸克和1个d夸克组成，中子由1个u夸克和2个d夸克组成
D．质子由2个u夸克和1个d夸克组成，中子由1个u夸克和1个d夸克组成
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When my son, Justin, was four, he found a caterpillar（毛毛虫）and put it in a box. Each day he it fresh grass and leaves . In a few weeks, the caterpillar became fat and was ready to sleep. One morning we found had become a cocoon(茧). Justin was . He knew a moth（飞蛾）or butterfly was going to be . “Dad ! is happening. Come and look!” He shouted happily. We could clearly see the wings . A few days later, a beautiful black moth broke free from its cocoon. The next day, Justin took the outside and opened it, and the little moth flew out. It flew around the yard twice, , and landed on Justin’s arm. He picked it up and threw it in the air, the moth came back again. He tried over and over to set it free, but each time it would return to his arm. I believe the moth, just like a person, was afraid to comfortable places and situations. It wanted to stay with something and was afraid to move on and experience new things. I was once that little moth. My cocoon was my mother’s love which made me comfortable. the moth, I didn’t want to fly too far from it. When my first job required me to move to a new city, I was but later I chose to move there. And finally, I found I was happy about my . Humans are animals of habit. We change. However, if we hadn’t moved, we would not have experienced many new things. So spread your wings and fly.
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手机是人们常用的通讯工具，下列说法不正确的是（ ）
A．手机靠电磁波传递信息
B．给手机电池充电时，电能转化为化学能
C．用手机接电话时靠声音的响度分辨对方是谁
D．将手机放在密闭金属容器中，别人将无法打通该手机
魔芋是天南星科多年生草本植物，具有行於散结，解毒消肿等功效．魔芋所含的有效成分葡甘聚糖还有降血脂、降血糖、减肥等作用．我市有些地方盛产魔芋．小明同学善于观察生活并能勤于思考，他的妈妈告诉他：魔芋在生长期不能施草木灰做肥料，否则魔芋难于生长．
提出问题：魔芋与草木灰为什么不相容？
实验探究：
（1）获取魔芋汁和草木灰水．取来魔芋，切成小片，放入研钵研压，加入少量蒸馏水，然后 ，得到魔芋汁；将草木灰放入烧杯中，加入少量蒸馏水，搅拌，静置，然后 ，得到草木灰水．
（2）测魔芋汁和草木灰水的PH．测其PH的操作是 ，测得魔芋汁的PH为7，则它呈 性，草木灰水PH为10，则它呈 性．
（3）取少量魔芋汁于试管里，加入少量草木灰水，观察到魔芋汁慢慢凝聚成豆腐状．再取魔芋汁于另一试管里，加入少量氢氧化钠溶液，观察到同样的现象．做后一步实验的目的是 ．获得的结论是 ．
我还想再探究的一个新问题是： ．
瓦斯浓度高于16%时，瓦斯不会爆炸也不会燃烧。
下列表述不正确的一项是( )。
A．项目决策阶段的基本特征是技术密集性
B．项目设计阶段的基本特征是智力和技术的双重性
C．项目施工阶段的基本特征是资金和劳动的双重性
D．项目终结阶段从一般意义上讲只是一种探索项目投资的事后控制和检验评价的规律和方法