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【简答题】
海水是丰富的资源宝库，从海水中提取元素是化学工业的重要组成部分。 （1）粗盐精制就是除去其中的Ca 2+ 、Fe 3+ 、SO 4 2- 及泥沙等杂质，需加入的试剂有：①Na 2 CO 3 溶液 ②HCl（盐酸） ③Ba（OH） 2 溶液，这三种试剂的添加顺序是_________（填序号）。 （2）用氯气进行“海水提溴”中制取溴单质反应的离子方程式为：__________。 （3）某同学设计了如图装置进行以下电化学实验。 ①当开关K与a连接时，两极均有气泡产生，则阴极为_______极。 ②一段时间后，使开关K与a断开、与b连接时，虚线框内的装置可称为__________。请写出此时Fe电极上的电极反应式_________________。 （4）某公厂向CaSO 4 悬浊液的反应通入氨气欲制取氮肥（NH 4 ） 2 SO 4 ，效果不好。再通入CO 2 ，则逐渐产生大量（NH 4 ） 2 SO 4 。请分析其原因 。
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【单选题】关于计算机语言，下列叙述正确的是（）。
A.
高级语言是与计算机型号无关的计算机语言
B.
低级语言学习使用很难，运行效率也低，所以已被高级语言淘汰
C.
汇编语言程序是最早出现的高级语言
D.
计算机能够直接理解、执行汇编语言程序
【简答题】Why don’t your parents let you drink dirty water?
【简答题】Why did the parents mentioned in the third paragraph leave the child alone in a room?
【单选题】Why are parents feeling more comfortable now?
A.
Technology keeps parents informed of their children.
B.
Websites give children information about their parents.
C.
Computer programmes help children do different activities.
D.
Parents' phones are now updated with children's pictures.
【简答题】A．Why his parents wanted to go to Gettysburg. B．Why his family's vacation plans changed ten years ago. C．Where his family went for a vacation ten years ago. D．When his family went on their last vacati...
【简答题】Why did the parents mentioned in the fourth paragraph leave the child alone in a room?
【单选题】Why do the parents choose private school for their children?
A.
The parents choose private school mainly because they give religious instructions that can’t be done in public schools.
B.
The parents choose private school mainly because the tuition there is very low
C.
The parents choose private school mainly because they are located near their houses.
D.
The parents choose private school mainly because they are safer and have higher academic standards than public schools.
【单选题】关于计算机语言,下列叙述正确的是________。
A.
计算机能够直接执行理解、执行汇编语言程序
B.
汇编语言程序是最早出现的高级语言
C.
低级语言学习使用很难,运行效率也低,所以已经被淘汰
D.
高级语言是与计算机型号无关的计算机语言
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