在加入酚酞变红色的无色溶液中，下列各组离子能够大量共存的是（_爱下问搜题

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问题选择题

在加入酚酞变红色的无色溶液中，下列各组离子能够大量共存的是（）

A．NH₄⁺、Na⁺、Cl^-、SO₄^2-

B．MnO₄^-、K⁺、NO₃^-、SO₄^2-

C．Ag⁺、NO₃^-、I^-、H⁺

D．ClO^-、Na⁺、NO₃^-、K⁺

答案

答案：D

加入酚酞变红色的无色溶液为碱性溶液，所以

A错，NH₄⁺在碱性溶液中会发生反应；B错，MnO₄^-离子的溶液为紫红色；C错，Ag⁺与I^-能反应不能共存，且氢离子在碱性溶液中也不能共存；D正确；

单项选择题

（）电梯俗称ACVV电梯.

A.交流变极极调速

B.交流调频调速

C.液压

D.交流调压调速

完形填空

阅读下面短文，从短文后各题所给的四个选项（A、B、C和D）出可以填入空白的最佳选项，并在答题卡上将该项涂黑
Even though it was only October, my students were already whispering about Christmas plans. With each passing day everyone became more __36__, waiting for the final school bell. Upon its _37____everyone would run for their coats and go home, everyone except David
David was a small boy in ragged clothes. I had often _38___what kind of home life David had, and what kind of mother could send her son to school dressed so __39__for the cold winter months, without a coat, boots, or gloves. But something made David __40__. I can still remember he was always __41____a smile and willing to help. He always __42__after school to straighten chairs and mop the floor. We never talked much. He__43___just smile and ask what else he could do, then thank me for letting him stay and slowly__44___home
Weeks passed and the __45___ovre the coming Christmas grew into restlessness until the last day of__46__before the holiday break. I smiled in ___47 __as the last of them hurried out the door. Turning around I saw David ___48___standing by my desk.
“I have something for you”he said and ____49____from behind his back a small box. __50___it to me, he said anxiously. “Open it,”I took the box from him, thanked him and slowly unwrapped it. I lift the lid and to my __51__saw nothing. I looked at David‘s smiling face and back into the box and said. “The box is nice, David, but it’s__52__”
“Oh no it isn’t,”said David. “It’s full of love, my mum told me before she died that love was something you couldn’t see or touch unless you know it’s there”
Tears filled my eyes ___53___Iooked at the proud dirty face that I had rarely given____54___to. After that Christmas, David and I became good friends and I never forgot the meaning ___55___the little empty box set on my desk

C．inaccurately

D．inappropriately

B．expectation

C．appreciation