英语周报HZE第14期答案

20.BD【解析】由开普勒第三定律(R+h)3T23(R+H+h7,A项错误;由开普勒第二定律可知探测器与火星连线在相等时间内扫过的面积相等,在极短的时间内有2(R+h)=v(R+H),可得RB项正确;探测器沿椭圆轨道运动满足机械R+H能守恒,但重力加速度随高度变化,C项错误根据万有引力提供向心力得CMmm2和(R+HGMm(R+h)2R+H=ma3,则R-th)2,D项正确。

书面表达One possible version:NOTICEA sports meeting will be held in the playground of our school from next Thursday to FridayAs you know, the pressure of study is very heavy now, especially for those senior 3. So the purpose of the sports meeting is to letevery student get relaxed, as a result of which we students can live happily and heal thilyEveryone is welcome to take part in it. Those who perform excellently at the sports meeting will get prizes. But don' t take theresults so serously because taking part is more important than the result. Good luck to everyone!

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