奖罚制度

关于凸透镜成像的一道科学题目凸透镜成像时,若测得物距U＝25厘米,像距V＝15厘米,则该像是什么像?（实象还是虚象）,该透镜的焦距一定大于几厘米?小于几厘米? 科学凸透镜成像问题搞不懂求表格和意思 初一下科学第一章 凸透镜成像问题 急.在u＞2f时,v=多少?最好再给我讲解一下照相机、放大镜、幻灯机（投影仪）的工作原理.U=多少时，V=多少？眼睛里各个结构的作用 有关泼水节的作文600字, we should do we can do to help forests.什么句式?为什么can 后面加的是to do对不起，写错了，是we should do we can to help forests lml=3,lnl=2,且m÷n＜0,求3m-2n的值 若m·n不等于零,则m\lml+n\lnl的值为------.lml指m的绝对值 lnl指n的绝对值 m\lml是个分数 n\lnl也是个分数 若lml=2,lnl=5,且m>n,则m+n=? They couldn't find the right way in the forest soon 改为同义句 lml=5,lnl=3且mn>0求：（m+n)-(-lm-nl)的值 lml=lnl那么m和n的关系是( ) They didn’t find angthing in the bushes.同义句转换They______ ______in the bushes. these are food kike the food of many years ago 选择___the enormous flow of food from the entire globe,these countries have for many years not___the enormous flow of food from the entire globe,these countries have for many years not felt any population pressurea,thanks to b,by means of c,in l The English Chinese food very much.A:like B:likes C:are like D:are liking For many years the earth has been unable to provide enough food for these rapidly expanding populations and the position is steadily deteriorating since the fertility of some of our richest soils has been lost and vast areas that were once fertile la curious的比较级是curiouser还是more curious? Let is have a picnic 改错怎么改? 若m,n满足如下关系,m>0,n 若m大于0,n小于0,且|m|大于|n|,用"大于号”把m、-m、n、-n连接起来. 一直下雨不晴天怎么办?谁有办法解决一下. Nothing is possible.I belive you well succeed什么意思 Nothing is in possible请问么子意思`! 呵呵` impossible is I'm possible的意思 after having lived for over twenty years in the same district, albert hall w英译汉 not having finished his homework,he had to having lived in here for many years,he knows两个句子都是用现在分词的完成时做状语,而句子的时态一个是一般现在时,一个是一般过去时,这样可以吗?第二个句子是：hav I am aslo fluent in Italian having lived in Rome for the summer in 2006.这句话什么时态呢? Children have a natural ___(curious) about the world around them.填空翻译谢谢 求女人发怒的样子 你会表达愤怒吗 用英语形容发怒的人的样子,谢如题比如暴跳如雷,龇牙咧嘴,张牙舞爪用英语白话表示一下 欲钱买形象极度愤怒的动物是什么欲钱买形象极度愤怒的动物是什么 (我说的是动物，不是人。是十二生肖里的）