简述利率在经济中的作用。

There was once a man called Mr. Flowers, and flowers were his only joy in life. He spent all his spare time in one of his four glass-houses and grew flowers of every color, with long and difficult names, for competitions, he tried to grow a rose of a new color to win the silver cup(银杯) for the Rose of the Year.

Mr. Flowers’ glass-houses were very close to a middle school. Boys of around thirteen years of age were often tempted to throw a stone(石头) or two at one of Mr. Flowers’ glass-houses. So Mr. Flower did his best to be in or close by his glass-houses at the beginning and end of the school day.

But it was not always possible to be on watch at those times. Mr. Flowers had tried in many ways to protect his glass, but nothing had been useful. He had been to report to the headmaster, but this bad not done any good. He had tried to drive away the boys when they threw stones. He had even picked up all the stones around his garden, so that the boys would have nothing to throw, but they soon found others.

At last Mr. Flowers had a good idea. He put up a large notice. It was made of good, strong wood. It was some meters away from the glass-houses. On it he had written the words: DO NOT THROW STONES AT THIS NOTICE. After that, Mr Flowers had no further trouble: The boys were much more attempted to throw stoned at the notice than at the glass-houses.

小题1:It was Mr. Flowers’ hope to ____

A．build glass-houses in his spare time

B．grow the rose in a glass-house

C．win a silver cup for growing a rose of a new color

D．grow a rose with the longest name小题2:Boys were often tempted to ____

A．throw stones at Mr. Flowers’ glass-houses

B．throw stones at Mr. Flowers from their school

C．be in or close by Mr. Flowers’ glass-houses

D．play with Mr. Flowers near his glass-houses小题3:Mr Flowers stayed in or close by his glass-houses ____

A．at times when school-boys were walking near them

B．all the school day when there were no boys around

C．where he could not be seen by the boya passing

D．in his spare time at the beginning and end of the school day小题4:Mr. Flowers had tried to ____ to protect his glass.

A．be on watch in his spare time

B．ask the headmaster for help

C．pick up all the stones around his garden

D．do all the above小题5:Mr. Flowers’ good idea was to ____

A．write some words on the glass

B．put up a larger notice to cover his glasshouses

C．give the boys something else to throw stones at

D．send for policemen

有A、B两个最小容积相等的恒温密闭容器，A能通过扩大容积而保持恒压，B能保持恒容。起始时向A、B中均通入2molSO₂和1molO₂后，A的容积扩大了5倍，在一定条件下反应开始进行并在一定时间后达到平衡。则下列说法中不正确的是 [ ]

A．达到平衡时，SO₂的转化率：A＜B

B．起始时的反应速率：A＜B，反应完成时的平均速率：A＜B

C．达到平衡后再充入等量氩气，A、B中平衡均不发生移动

D．达到平衡后再向A中充入等量的原反应气体，再次平衡时SO₂的质量分数与前次等。

利用化学原理对工厂排放的废水、废渣等进行有效检测与合理处理。

(一)染料工业排放的废水中含有大量有毒的NO₂^-，可以在碱性条件下加入铝粉除去(加热处理后的废水会产生能使湿润的红色石蕊试纸变蓝的气体)。除去NO₂^-的离子方程式为________。

(二)某工厂对制革工业污泥中Cr(Ⅲ)回收与再利用工艺如下(硫酸浸取液中金属离子主要是Cr^3＋，其次是Fe^3＋、Fe^2＋、Al^3＋、Ca^2＋、Mg^2＋)：

常温下部分阳离子以氢氧化物形式沉淀时溶液的pH见下表：

(1)酸浸时，为了提高浸取率可采取的措施是________(至少写一条)。

(2)调pH＝8是为了除去________(填Fe^3＋、Al^3＋、Ca^2＋、Mg^2＋)。

(3)钠离子交换树脂的原理为M^n＋＋nNaR→MR_n＋nNa^＋，被交换的杂质离子是________(填Fe^3＋、Al^3＋、Ca^2＋、Mg^2＋)。

(4)试配平氧化还原反应方程式：□Na₂Cr₂O₇＋□SO₂＋□H₂O = □Cr(OH)(H₂O)₅SO₄＋□Na₂SO₄；每生成1mol Cr(OH)(H₂O)₅SO₄消耗SO₂的物质的量为________。

(三)印刷电路铜板腐蚀剂常用FeCl₃。腐蚀铜板后的混合浊液中，若Cu^2＋、Fe^3＋和Fe^2＋的浓度均为0.10mol·L^－1，请参照上表给出的数据和提供的药品，简述除去CuCl₂溶液中Fe^3＋和Fe^2＋的实验步骤：①________；②________；③过滤。(提供的药品：Cl₂、浓H₂SO₄、NaOH溶液、CuO、Cu)。

在做铁丝在氧气中燃烧实验时，要预先在集气瓶中装少量 _____ 或铺一层细砂，是为了 _________________________

个人质押贷款一般最高不得超过质押物价值的90%。