如图所示，有一底面积为S=1000cm²，高1.5m的圆柱形盛水容器中竖直放置一底面积为S=200cm²，高h=20cm的圆柱形物块：己知该物块的密度为ρ=2.5×10³kg/m³，容器中水深H=1.2m．开始时，物块下表面与容器底面间有小空隙，现用如图所示的光滑轻滑轮组拉着物体以v=0.2m/s的速度匀速上升．（取g=10N/kg，不计水的阻力，ρ_水=1.0×10³kg/m³）

短文改错

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。每处错误仅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：在错的词下划一横线，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。

    Last week we held a discussion on which we should do for our school before we graduate．The students in our class have different suggestion．Some students thought that we can collect money to buy some books for the school library or everything else for the schoo1．Other students argue that there's not necessary to spend money．We can study hard and make our school feeling proud of us．

    In my opinion, we don't have to spend money. We can do something meaningfully without money. For an example，we can do some voluntary work to beautify the school and try to get better results in the coming exams so that our school will proud of us．