抛物线y＝ax2+bx+c与x轴交于A，B两点，与y轴交于C点，且经过点(2，-3a)，对称轴是直线

If you do not use your arms or your legs for some time,they become weak:when you start using them again,they slowly become strong again.Everybody knows that.Yet many people do not seem to know that memory works in the same way.When someone says that 用花名补充诗句有情( )含春泪.采( )东篱下.却道( )依旧.休向耳边蹄( ) _____they_____(get)to the farm on time last monday?用所给单词的适当形式填空___they___(get)to the farm on time last Monday?为什么是did,get而不是had get i'm sorry to have kept you waiting for a long timewaiting可以不加ING吗?为什么? I’m awfully sorry to have kept you waiting for a long time.A、Just tell me the reason.B、You shouldn’t have said so.C、No problemD、Actually,I’ve only been here for twenty minutes应该选择哪个? 对不起,让你等了这么久.I'm sorry to have kept you___ ___ ___a long time. 小孔成像说明____________________________,小孔成__________像. 小孔成像的现象可以用什么来解释 帮我解释一下小孔成像现象为什么成倒立像呢 什么是名词分句和副词分句,怎么分辨,如tell me when she will com back和 tell me when she comes back 七下英语连词成句 news,she,comes,I'll,when,tell,the,her(.)【陈述句】 If you don't tell your sister the truth,she will be angry{改为同义句}▁▁▁you▁▁▁your sister the truth,she will get angry. 党是阳光我是花作文,狂求! I'm sorry.Why I have cheated you long.I feel very ashamed of that,I hope you can forgive me. I'm sorry that I didn't write back to you sooner but I have been very busy and tired.翻译 Could you tell me___tomorrow morning?Awhen the meeting will start Bwher will the meeting startCwhere the meeting startsDwhen the meeting would start Can you tell me______ A.when you will be free tomorrow B.when you are free tomorrow选择哪个? I heard someone_______(cry)in the next room a moment ago I heard someone________ (cry) in the next room a moment ago.用所给词的适当形式填空. 党是阳光我是花作文 this morning i heard her ——（cry)in the next room. 作文 党是阳光我是花 党是阳光我是花 作文 在学习上,老师要求我们独立思考,互相合作,积极探讨. They have been here once.把been换成came怎么样 I came here for my schoolbag.这里的came为什么要用过去式? can you tell me when you ___ if it ___ tomorrow?A:arrive; doesn't rainB:will arrive; won't rain C:will arrive; doesn't rain He heard someone singing in the next room.请问这里的宾补sing为什么加的是ing?而不是ed或者是不定式?按道理来说,前面heard用过去式,后面sing也要用过去式啊?到底宾补在什么状态下要用什么式? I heard a girl singing in the next room 改为同义句 I heard that a girl ___ ___in the next room it was 25 years ago he graduated from harvard universityit was 25years ago （）he graduated from harvard university选那个？1since2before3that4after 英语中I am sorry to hear that和I am sorry to heard that有什么区别? It was six years ago( )the teacher graduated from our college.A.that B.when C.when that D.since