问题 应用设计题

如图所示,考古人员需要对一口古井进行清理,为了解决照明问,请你帮他们把太阳光反射到井里,并能垂直照亮井底。

答案

如图所示

光的反射定律:反射光线与入射光线、法线在同一平面上;反射光线和入射光线分居在法线的两侧;反射角等于入射角。可归纳为:“三线共面,两线分居,两角相等”。

由以上光的反射定律可知,法线就是入射光线与反射光线夹角的角平分线,镜面与法线垂直。

所以作图时先做入射光线与反射光线夹角的角平分线,(用虚线),再作角平分线的垂线,画上斜线表示镜子的背面。

点评:本题主要考查光的反射作图,是常见题。注意作图规范性。

完形填空
I used to have little passion(激情,热情)in my life. But what happened the other day changed my mind. It was then that I learned how        it is to have a passion in life.
That day I went home in Mom’s car. When Mom        at a red light, someone on the side of the road caught my eye. It was a man dressed        rags. He was homeless. That didn’t interest me, because I had seen         like him before. Those people usually looked unhappy and hopeless.
But this man was        in some way. He was not sitting down with a        expression. Instead, he had a         in his hand and was dancing happily to the music. The radio seemed to be the most precious thing he had.
“Mom, why does that man have a radio        he’s homeless?” I asked.
“He       it, “ she replied.
“But why doesn’t he use the money to buy food or clothes? He       something that he didn’t need.”
“Well, Sarah, sometimes food and clothes aren’t the most important.”
That man must care so much about        that he bought a radio instead of food or clothes. I soon realized that        is the key to life.
Since then I am always thinking of        is truly important in life. A home, a meal, clothes – these things are        part of the life. What we often forget is that we all need a joy, a light on a         day. We all need a passion which gives a person the happiness they need to keep going.
小题1:
A.strangeB.importantC.dangerousD.difficult
小题2:
A.stoppedB.walkedC.stoodD.exercised
小题3:
A.inB.onC.atD.of
小题4:
A.noneB.fewC.allD.many
小题5:
A.commonB.differentC.politeD.rude
小题6:
A.sadB.nervousC.politeD.rude
小题7:
A.hatB.phoneC.scarfD.radio
小题8:
A.thoughB.becauseC.untilD.unless
小题9:
A.borrowedB.madeC.fixedD.bought
小题10:
A.asked forB.waited forC.paid forD.looked for
小题11:
A.storiesB.musicC.newsD.languages
小题12:
A.knowledgeB.healthC.happinessD.friendship
小题13:
A.whoB.whatC.whereD.when
小题14:
A.onlyB.allC.alsoD.never
小题15:
A.warmB.hotC.darkD.relaxing
单项选择题