题干

实验是化学研究的基础,关于下列各实验装置图的叙述中,错误的是

A:装置①当止水夹关闭,而后从长颈漏斗注水操作可用于检查该装置的气密性

B:装置②可用于除去CO中混有的少量CO2

C:装置③可用于从海水中得到淡水

D:装置④可用于排空气收集CO

上一题 下一题 0.0难度 选择题 更新时间:2019-03-06 07:26:15

答案(点此获取答案解析)

D

同类题3

根据短文理解,选择正确答案。

    Watching some children trying to catch butterflies one hot August afternoon, I was reminded of an incident in my own childhood.When I was a boy of 12 in South Carolina, something happened to me that cured me forever of wanting to put any wild creature in a cage.

    We lived on the edge of a wood, and every evening at dusk the mockingbirds would come and rest in the trees and sing. There isn't a musical instrument made by man that can produce a more beautiful sound than the song of the mockingbird.

    I decided that I would catch a young bird and keep it in a cage and in that way would have my own private musician.

    I finally succeeded in catching one and put it in a cage. At first, in its fright at being captured, the bird fluttered about the cage, but eventually it settled down in its new home. I felt very pleased with myself and looked forward to some beautiful singing from my tiny musician.

    I had left the cage out on our back porch, and on the second day of the bird's captivity my new pet's mother flew to the cage with food in her mouth. The baby bird ate everything she brought to it. I was pleased to see this. Certainly the mother knew better than I how to feed her baby.

    The following morning when I went to see how my captive(被俘虏的) was doing, I discovered it on the floor of the cage, dead. I was shocked! What had happened! I had taken excellent care of my little bird, or so I thought.

    Arthur Wayne, the famous ornithologist, happened to be visiting my father at the time, hearing me crying over the death of my bird, explained what had occurred. “A mother mockingbird, finding her young in a cage, will sometimes bring it poison berries. She thinks it better for her young to die than to live in captivity.”

    Never since then have I caught any living creature and put it in a cage. All living creatures have a right to live free.