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问题 填空题
lim
n→∞
(
n2+2n
-n)=______．
答案

原式=

lim
n→∞
(
n2+2n
-n)(
n2+2n
+n)
n2+2n
+n

=

lim
n→∞
2n
n2+2n
+n

=

lim
n→∞
2
1+
2
n
+1

=1．

故答案是1．

完形填空

小题1:________ Betty __________ (study) in this school since she came here in 2008?

小题2: ---Must the children _____________ (teach) how to cook when they are at home alone?

---Of course. It is necessary for them to learn how to cook.

小题3:I didn’t catch what you said just now because I_________ (answer) a call from my aunt.

小题4:----Why did John look so unhappy?

----Because he _______________ (not reply) to his wife by the time he left for Paris.

小题5: Usually before exams, the students ____________(give) five minutes to write their names and read through the paper.

小题6:Simon ____________ (take) a lot of photos while he was in Shanghai. He will show them to us when he returns.

小题7:The weather report said that the bad weather ______________ (last) for two days. What shall we do?

小题8:Having the robot _______________ (do) all the housework is really great. I can get more free time for my hobbies.
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实验题

某课外活动小组加热炭粉（过量）和氧化铜的混合物，再用下图装置，对获得的铜粉（含炭）样品进行实验。图中铁架台等装置已略去。请你帮助他们完成下列实验报告。

（1）实验目的：测定铜粉样品中铜的质量分数

（2）实验用品：仪器：天平、分液漏斗、锥形瓶、硬质玻璃管、干燥管、酒精灯、洗气瓶等，药品：红褐色铜粉（含炭）样品、过氧化氢溶液、二氧化锰、碱石灰、浓硫酸等。

（3）实验内容（见表1）表1 实验步骤、现象及化学方程式：

（4）计算：样品中铜的质量分数＝______。（用含W、m1、m2的代数式表示。）

（5）问题和讨论：实验完成后，老师评议说：按上述实验设计，即使C中反应完全、D中吸收完全，也不会得出正确的结果。经讨论，有学生提出在B与C之间加入一个装置，再次实验后，得到了较正确的结果。那么，原来实验所测得的铜的质量分数偏小的原因可能是__________。在B与C之间加入的装置可以是_____________，其中盛放的药品是____________。
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