题干

蜜蜂飞行时,它的翅膀平均每秒钟振动40次,蝴蝶飞行时,它的翅膀平均每秒钟振动5~6次,它们飞行时的音调(   )

A:蜜蜂的较高

B:蝴蝶的较高

C:一样高

D:无法确定

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答案(点此获取答案解析)

A

同类题3

阅读下面的文言文,完成文后各题。

    谢景仁,陈郡阳夏人,名与高祖同讳,故称字。祖据,太傅安第二弟。父允,宣城内史。景仁幼时与安相及,为安所知。始为前军行参军。会稽王世子元显嬖人张法顺,权倾一时,内外无不造门者,唯景仁不至。年三十,方为著作佐郎。桓玄诛元显,见景仁,甚知之,谓四坐曰:“司马庶人父子云何不败,遂令谢景仁三十方作著作佐郎。”玄为太尉,以补行参军,府转大将军,仍参军事。

    景仁博闻强识善叙前言往行玄每与之言不倦也玄出行殷仲文卞范之之徒皆骑马散从而使景仁陪辇。高祖为桓修抚军中兵参军,尝诣景仁咨事,景仁与语悦之,因留高祖共食。食未办,而景仁为玄所召。玄性促急,俄顷之间,骑诏续至。高祖屡求去,景仁不许,曰:“主上见待,要应有方。我欲与客共食,岂当不得待。”竟安坐饱食,然后应召。高祖甚感之,常谓景仁是太傅安孙。及平京邑,入镇石头,景仁与百僚同见高祖,高祖目之曰:“此名公孙也。”义熙五年,高祖以内难既宁,思弘外略,将伐鲜卑;朝议皆谓不可。刘毅时镇姑孰,固止高祖,以为:“苻坚侵境,谢太傅犹不自行。宰相远出,倾动根本。”景仁独曰:“公建桓、文之烈,应天人之心,匡复皇祚,芟夷奸逆,虽业高振古,而德刑未孚,宜推亡固存,广树威略。鲜卑密迩疆甸,屡犯边垂,伐罪吊民,于是乎在。平定之后,养锐息徒,然后观兵洛汭,修复园寝,岂有坐长寇虏,纵敌贻患者哉!”高祖纳之。

    及北伐,转景仁为大司马左司马,专总府任,右卫将军,加给事中,又迁吏部尚书。八年,迁领军将军。十一年,转右仆射,仍转左仆射。十二年,卒,时年四十七。追葬日,高祖亲临,哭之甚恸。

(选自《宋书》卷五二,列传十二。有删减)

同类题4

阅读下列短文,从每题所给的四个选项(A、B、C和D)中,选出最佳选项。

       Each new school year brings fresh reminders of what educators call the summer learning gap. Some call it the summer learning setback. Simply speaking, it means the longer kids are out of school, the more they forget. The only thing they might gain is weight.

       Most American schools follow a traditional nine-month calendar. Students get winter and spring breaks and about ten weeks of summer vacation. Some schools follow a year-round calendar. They hold classes for about e ight weeks at a time, with a few weeks off in between. The National Association for Year-Round Education says there were fewer than three thousand such schools at last count. They were spread among forty-six of the fifty states.

       But many experts point out that the number of class days in a year-round school is generally the same as in a traditional school. Lead researcher Paul von Hippel said, “Year-round schools don't really solve the problem of the summer learning setback. They simply spread it out across the year.”

Across the country, research shows that students from poor families fall farther behind over the summer than other students. Experts say this can be prevented. They note that many schools and local governments offer programs that can help.

       But calling them “summer school” could be a problem. The director of the summer learning center at Johns Hopkins, Ron Fairchild, said research with groups of different parents in Chicago and Baltimore found that almost all strongly disliked the term “summer school”. In American culture, the idea of summer vacation is connected to beliefs about freedom and the joys of childhood. The parents welcomed other terms like “summer camp”, “enrichment”, “extra time” and “hands-on learning”.