题目

古代的侦察兵为了及早发现敌人骑兵的活动，常常把耳朵贴在地面上听，以下解释错误的是A. 马蹄踏在地面时，使土地振动而发声 B. 马蹄声可以沿土地传播C. 马蹄声不能由空气传到人耳 D. 土地传播声音的速度比空气快 答案：【答案】C【解析】试题古代的侦察兵把耳朵贴在地面上，从而能够及早的发现敌人的活动情况，是利用了不同介质中，声音的传播速度不同的原理，可据此进行解答．解：由于声音在固体中的传播速度比在空气中的传播速度要快，因此古代的侦察兵把耳朵贴在地面上，能更早的听到敌人骑兵的活动情况When you are little, the whole world feels like a big playground. I was living in Conyers, Georgia the summer it all happened. I was a second grader, but my best friend Stephanie was only in the first grade. Both of our parents were at work and most of the time they let us go our own way.It was a hot afternoon and we decided to have an adventure in Stephanie's basement. As I opened the basement door, before us lay the biggest room, full of amazing things like guns, dolls, and old clothes. I ran downstairs, and spotted a red steel can. It was paint. I looked beyond it and there lay even more paint in bright colors like purple, orange, blue and green."Stephanie, I just found us a project for the day. Get some paintbrushes. We are fixing to paint. " She screamed with excitement as I told her of my secret plans and immediately we got to work. We gathered all the brushes we could find and moved all of our materials to my yard. There on the road in front of my house, we painted big stripes (条纹) of colors across the pavement (人行道). Stripe by stripe, our colors turned into a beautiful rainbow. It was wonderful!The sun was starting to sink. I saw a car in the distance and jumped up as I recognized the car. It was my mother. I couldn't wait to show her my masterpiece. The car pulled slowly into the driveway and from the look on my mother's face, I could tell that I was in deep trouble.My mother shut the car door and walked towards me. Her eyes glaring, she shouted, "What in the world were you thinking? I understood when you made castles out of leaves, and climbed the neighbors' trees, but this! Come inside right now !" I stood there glaring back at her for a minute, angry because she had insulted (侮辱) my art."Now go clean it up!" Mother and I began cleaning the road. Tears ran down my cheeks as I saw my beautiful rainbow turn into black cement.Though years have now passed, I still wonder where my rainbow has gone. I wonder if, maybe when I get older, I can find my rainbow and never have to brush it away. I guess we all need some sort of rainbow to brighten our lives from time to time and to keep our hopes and dreams colorful.1. What did the writer want to do when his mother came home?A. To introduce Stephanie to her.B. To prevent her from seeing his painting.C. To put the materials back in the yard.D. To show his artwork to her.2. In his mother's eyes, the writer ____________.A. was a born artistB. always caused troubleC. was a problem solver D. worked very hard3. The underlined word “rainbow” in the last paragraph refers to_________.A. the rainbow in the skyB. the stripes on the pavementC. something imaginative and funD. important lessons learned in childhood4. It can be learned from the passage that parents should .A. encourage children to paintB. value friendship among childrenC. discover the hidden talent in childrenD. protect rather than destroy children's dreams