波从一种介质进入另一种介质时,其传播速度、频率和波长则( )。 A.(A) 都不发 发布时间:2018-07-03 19:39 │ 来源:www.tikuol.com 题型:单项选择题 问题: 波从一种介质进入另一种介质时,其传播速度、频率和波长则( )。A.(A) 都不发生变化B.(B) 速度和频率变化,波长不变C.(C) 都发生变化D.(D) 速度和波长变化,频率不变
题型:单项选择题 A local elementary school has requested scoliosis screening for its students from the hospital’s community outreach program. The school should be informed thatA. these students are too young to screen; instead, older students should be screened.B. these students are too old to screen and will no longer benefit from screening for scoliosis.C. scoliosis screening requires sophisticated equipment and can’t be done in school.D. this is an appropriate request and arrangements will be made as soon as possibl 查看答案
题型:单项选择题 阅读下面这首诗,回答问题。(共7分)村夜 白居易霜草苍苍虫切切,村南村北行人绝。独出门前望野田,月明荞麦花如雪。小题1:出门前后,诗人的心情有变化吗?试作简述。(3分)答:________________________________________小题2:《唐宋诗醇》称白居易的《村夜》:“一味真朴,不假妆点,自具苍老之致。”你认为这样的评价合理吗?为什么?(4分)答:____________________________________ 查看答案