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（1）如图是小红同学组装的用过氧化氢溶液和二氧化锰粉末制取氧气的简易装置．请你写出发生反应的化学方程式______，二氧化锰在此反应中所起的作用是______． （2）小明同学发现使用此装置在收集完氧气后，反应还在继续进行．他认为，这个装置的缺点是不能控制反应随时发生、随时停止，造成了药品的浪费．为了解决小明提出的问题，请你对原实验装置加以改进或设计新的简易实验装置，以便有效地控制反应的进行． 友情提示：你可从下列用品中选取，也可自行选用其它常用的简单仪器． 请你在下表中至少写出两种方案： 方案一 方案二 ______ ______
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举一反三
【简答题】____ 8. They had ______ such difficulty that they almost gave the project up.
【简答题】Change the sentences so that they use inversion. 8. They had met such rude people nowhere before.
【单选题】No sooner ____themselves in their seats in the theatre ____the curtain went up. A. they have settled, before B. had they settled, than C. have they settled, when D. they had settled, than
A.
B.
C.
D.
D
【简答题】Her skeleton was small and spare; perhaps that was why what would have been merely plumpness in another was obesity in her.(Para.6) 7. So the next night, after midnight, four men crossed Miss Emily's ...
【简答题】完形填空 。 One day two brothers went fishing. They had a dog with them. When they came near the river, they threw caps __ 1 __ a big stone and went to the river bank to __ 2 __. It __ 3 __ cold that day, ...
【单选题】They had participants organize different activities by time or to-do list to measure how they performed under “clock time” vs “task time”.
A.
措施
B.
较量,考验
C.
尺度,标准
D.
测量,判定
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