（1）如图甲所示，一束激光射到平面镜上的O点，画出其法线和反射光线，
（2）如图乙所示，画出光从水斜射入空气时折射光线的大概位置，
（3）根据平面镜成像特点，在图丙中画出物体AB所成的像．

在函数$y=\frac{x}{x-2}$中，自变量x的取值范围是____ ．

在下面一段文字横线处补写恰当的语句，使整段文字语意完整连贯，内容贴切，逻辑严密。每处不超过20字。

    苦难与幸福是相反的东西，但它们有一个共同之处，____，并且都牵涉到对生命意义的评价。在通常情况下，我们的灵魂是沉睡着的，____，它便醒来了。如果说幸福是灵魂的巨大愉悦，这愉悦源自对生命的美好意义的强烈感受，那么，苦难之为苦难，正在于它撼动了生命的根基，打击了人对生命意义的信心，因而使灵魂陷入了巨大痛苦。生命意义仅是灵魂的对象，对它无论是肯定还是怀疑、否定，只要是真切的，就必定是灵魂在出场。外部的事件再悲惨，____，也成为一个精神事件，就称不上是苦难。一种东西能够把灵魂震醒，使之处于虽然痛苦却富有生机的紧张状态，应当说必具有某种精神价值。

增加：在缺词处加一个漏词符号（∧），并在此符号下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：1).每处错误及其修改均仅限一词；

2).只允许修改10处，多者（从第11处起）不计分。

    Yesterday, as I was queuing at the checkout at a store, there was an old lady in the front of me in line. She seemed very confusing when the cashier asked her pay US$38. She had about US$5 in her wallet. The cashier told her that she could not buy the items because she didn't have enough money. So, I told the cashier I would pay for that she bought. Afterwards, I paid for all the items. When I got outside, the lady was standing there. While I was talking about her, her daughter appeared. She told me that her mother had Alzheimer's disease. Then she noticed that her mother had three bag of groceries and wondered how she managed to pay for them with enough money. I told her that I had paid for it. The daughter wanted to pay me back, so I refused. I believe make others feel good makes me feel good.

春秋时期是分封制逐渐走向解体的时期，由“礼乐征伐自天子出”变为“礼乐征伐自诸侯出”。这一时期最显著的政治特点是（　　）