直线在平面的投影

What do you do __ christmas?快 What do you do ___(clebtate)Christmas 对划线部分提问 Behind the door there's a book -------- ---------the book?对划线部分提问(Behind the door ) there's a book-------- ---------the book? 什么时候金属会有变价 fe在化学反应中的变价规律（追分）铁在跟哪些反应变2价哪些变3价（包括含铁的化合物）不要涉及太深奥的东西 What、which、what colour、what kind of的意思 请教“What do you do at Christmas"这里的介词为什么用at 而不是用on? what do you usually do----------christmas?怎么填, There ___(be) something difficult in the book -Lily has made a decision to study hard.-___-Lily has made a decision to study hard.-_____.A.so has heB.so have sheC.so she hasD.so she does paul doesn't have to be made to study.he is always a hard-working student.翻译+ . many students who survived ___ earthquake in sichuan Province have determined to study hard to makecontributions to the society in __future a the ;the写 b.不填；不填 l have to Study hard (一般疑问句) What do you do的同义句是什么What do you do?的同义句是什么 何谓变价金属 what do you do ?的同义句是什么 1 What do you do 同义句 _______ your ________?2 Mike was born (in 1992 in New York.)对括号内部分提问____ _____ _____ was Mike born? 关于化学中的元素变价元素的化合价决定于元素的最外层电子数,最外层电子数又是一定的,那么元素的变价是怎么回事?不是化合价而是如Fe2+和Fe3+之类的同一元素的不同化合价! What can I do for you的同义句是 寻求关于How to spend the money的英语作文 He had a litltle trouble _his tires.A.to B.fixing C.fixed D.fix应该选哪个 A.fix B.fixing C.fixed D.to fixI fell down and broke three of my teeth.I wonder how many times I have to come here and get my false teeth_____. My father's bike is broken.My father is busy _ .A.to fix it up B.fixing it up C.fixing up it The radio doesn't work well,it need_________ A fixing Bbeing fixed C to fix D fixed为什么?need doing = need to be done可是这里是用的doing,但是不是被修理吗?为什么不选B呢? i _______(make) the decision to study aboard to study hard can help to make your wish ___(com) ture. what do you usually do on christmas?翻译 what do you usually do on christmas?Ai an going tto have a partyBi eat delicioua foodci bought some giftsdi like christmas very much what do you usually 前面的助动词do有什作用,如果换成第三人称,是什么样? How to spend a Nice Weekend英语作文 70词左右假设你们学校英语俱乐部即将举办一场以“How to Spend a Nice Weekend"为题的演讲大赛,请你根据下列内容提示,写出一篇演讲稿.提示：1.和父母一起看电影2. 请问铜钝化后如何检测他的钝化效果,听说有什么耐腐蚀实验,还有什么结合力实验,那么什么输就最好呢? 如何提高镁合金的耐蚀性?