题目

如图所示，是某护城河上的一座吊桥．设吊桥的重力对转轴O的力臂为L1 ， 绳子拉吊桥的力为F，拉力F对转轴O的力臂为L2 ， 如果绳重、摩擦及风的阻力不计，那么在守桥士兵将吊桥由水平位置缓慢拉至图中虚线竖直位置的过程中，L1，L2，F。(填“增大”、“不变”或“减小”) 答案：【1】减小【2】增大【3】减小Miracles（奇迹）will happen if you don't give up trying. Even if you have for one hundred times, you may succeed when you try for the 10lst time.When I was born, my doctor told my mother that there was something wrong with my . They were too soft to be able to walk. Although the news was bad, my mother didn't become . She didn't believe what the doctor said started to look for other ways.My mother kept looking for other doctors for me, and finally she . The doctor and his team in the hospital did they could to help me. They also asked my parents to teach me to do some to help me walk. One day when my mother came to pick me . I crawled(爬) towards her. She was so surprised and happy that she couldn't believe eyes. Crawling was not walking, but it was a good . Day by day, I could walk by myself.When I grew up, my mother told me these stories. She said that if I thought of what she said whenever I met , I could do anything successfully. I have been working hard and I have turned out to be a very person. I get best in school and I am a good dancer and swimmer. Thanks to my mother's strong resolution(决心), I live a life now. What the story tells us, as my mother always says, is: Never give up.【1】A. achieved B. failed C. suggested D. told【2】A. legs B. hands C. arms D. eyes【3】A. patient B. confident C. frustrated(沮丧的) D. proud【4】A. or B. and C. if D. because【5】A. forgot B. changed C. succeeded D. worked【6】A. nothing B. somewhere C. anywhere D. everything【7】A. time B. exercise C. medicine D. shopping【8】A. away B. from C. into D. up【9】A. her B. my C. his D. its【10】A. advice B. end C. chance D. start【11】A. hardly B. never C. always D. nearly【12】A. dreams B. experiments C. jobs D. difficulties【13】A. excellent B. dangerous C. busy D. special【14】A. presents B. friends C. books D. grades【15】A. happy B. sad C. tired D. boring