如图所示，小球从倾斜轨道上由静止释放，经平直部分冲上圆弧部分的最高点A时，对圆弧的压力大小为mg，已知圆弧的半径为R，整个轨道光滑．则（   ）

下列对下图的分析，正确的是（    ）

①a~d环节联系了地球的各个圈层

②b环节直接为陆地降水输送大量水汽

③c环节对陆地淡水资源更新有重要意义

④d环节水量受地表植被条件影响不大

乾隆时，有人在咏花诗中写道“夺朱非正色，异种也称王”，结果被杀。其门生、印刻者、卖书者、买书者都被判刑。这主要反映了清朝(    )

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。错误涉及一个单词的增加、删除或修改。

增加：在缺词处加一个漏字符号(∧)，并在其下面写出该加的词。

删除：把多余的词用斜线(\)划掉。

修改：在错的词下画一横线，并在该词下面写出修改后的词。

注意：1)每处错误及其修改均仅限一词；

2)只允许修改10处，多者(从第11处起)不计分。

Dear Editor,

I'm the boy student in a key middle school in our city. I fond of play the piano. It is known by us that the college entrance examination is approaching. I must get good prepared for it. So I have only fifteen minutes to play the piano on every day. I don't want to give up my favorite, and my parents forbade me to continue playing it. They think it a waste of time to do it now. How do you think of it? Could you give me some advices on how to deal with the problem? I am looking forward to your early reply.

Thank you.

John