小明同学学习了“降水的形成”知识后，为家人做了“下雨”的实验_爱下问搜题

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问题选择题

小明同学学习了“降水的形成”知识后，为家人做了“下雨”的实验．他把盘子擦干放进冰箱里冷却，水壶装满水并烧开，这时水汽不断上升，壶嘴上方就出现一团“白气”，这就是“云”．从冰箱里取出盘子放在壶嘴上方约15cm的地方，盘子碰到这团“云”，一会儿盘的下表面就会布满水滴，水滴越积越多，越积越大，等到挂不住时就纷纷落下，这就是“雨”．下面关于实验现象的解释，正确的是（　　）

A．壶嘴上方出现的一团“白气”是壶中水汽化形成的气态水

B．壶嘴上方出现的一团“白气”是液态水

C．水汽化时放出热量

D．水滴下落时，只受重力和空气阻力的作用，因此一定匀速下落

答案

壶嘴上方“白气”是水蒸气遇冷发生液化现象变成的液态水，故B符合题意，A不符合题意；

C、水汽化过程需要吸收热量，不符合题意；

D、水滴下落时，刚开始重力大于空气阻力时做加速运动，只有当重力和空气阻力大小相等时会匀速下落，不符合题意；

故选B．

完形填空

“Welcome, Mary,” I said. She raised her head and looked into my eyes. The smile on my face 36 . Dear God, I thought, what   37  has entered the life of this little girl?
After settling Mary into her new desk and   38  her, I went to the headmaster. She said, “Sit down and I’ll   39  you in. Mary’s mother who loved her very much was shot and killed in her   40  one night at their house. Mary, screaming, escaped to a neighbor’s. Then the child went into   41 . She hadn’t cried or   42  her mother since.”
I returned only to discover that the children were already avoiding this “ 43 ” child. “Mary’s been hurt badly, but we can do a lot to help her,” I explained gently. Bless all children. How loving they can be   44 they understand.
In spite of our 45 , we seemed to be getting no closer to Mary and even my faith was wearing   46 . My heart ached so badly, wanting this child to come alive, to be aware of the beauty, the wonder, the fun, and even the   47  of living.
Spring approaching, children   48  to make flower baskets for room decoration. During the lunch time, a girl came hurrying to me. “Come to see Mary’s basket,” she said   49 . “You’ll never believe it!” I   50  my breath at its beauty, for it couldn’t have been the work from a child that   51 .
“Mary,” I said. “This is beautiful. How did you ever   52 ?” She looked at me with the shining eyes of any   53  little girl, saying, “My mother loved flowers.”
Thank you, God, You’ve   54  us the miracle(奇迹). I knelt and put my arms around the child. Then the tears came, slowly at first, but soon she was   55  her heart out against my shoulder. The other children had tears in their eyes, too, but theirs—like mine—were tears of joy.

A．introducing

单项选择题 A3型题

一奶牛场，3d前有一奶牛因突然发热，呼吸困难而迅速死亡，后来又有一头5岁奶牛发病，病牛体温升高达41.6℃，食欲废绝，精神沉郁，有痛性干咳，呼吸高度困难，头颈前伸，张口伸舌，鼻流白色泡沫。叩诊胸部，两侧肺部均有浊音区；听诊支气管呼吸音增强并有啰音。病牛腹泻，粪中有黏液和少量血液，恶臭该病最可能的诊断是（）

A.大叶性肺炎

B.牛出败（牛巴氏杆菌病）

C.牛肺疫

D.牛病毒性腹泻/黏膜病

E.口蹄疫