气球和飞艇是通过气球或气囊中的什么来改变浮力的大小

had,you,think,better,of,way,a,good连词成句 He said that he had never seen such a __________(Imagine) film before.词性转换 答案是unimagination.可是我想不通啊 The poilceman said that________seen the thief beforeA.I hadB.I haveC.he has D.he had选那个?为什麼.能给我解释下麼..我想弄明白.. 悲剧的人生翻译成英文是什么? 英语翻译 英语翻译那个电影我以前看过.yes or no "约莫"怎么造句?拜托各位大神 What do u want to do when u are alone?I don't know what to do when I am alone,because I really feel lonely.But lots of my friends like to stay at home alone to enjoy themselves,what about 校园之——— 不能出现人名,校名,地名 She said that she did her homework.如何变一般疑问句She said that she did her homework。如何变否定句句 She said that she did her homework.如何变否定句句 在一次套圈比赛中,一共要套20次,李青的命中率为60%,李青套中了几次? Are you a Are you a rabot意思 you are a ___do you want?------I want a CD of popular songsA.Which CD B.How many CDs C.What CD D.How much 我要解释 More and more foreigners want to（open up）their companies in Zhejiang.More and more foreigners want to (open up)their companies in Zhejiang.其他的选项肯定不对,但是这个选项在这表示什么?表示建立,建造?open up连在一起, you are 为什么不用you are a man? you are a kind You are a half man 我本想说一个老外懒,什么都要人帮忙,是半个人,可他好像很生气.我想知道这话会不会有特殊意义啊?他是德国人. (the)peope here are very friendly to us开头为什么用the 这句话对吗?when you think you understand everything,you are wrong 左眼皮跳代表什么,右眼皮跳代表什么? 考古学家常用碳－14的“半衰期”原理来判断文物年代,请问“半衰期”具体是多少年?A 5730年 B 6730年 C 7730年 D 8730年 碳14的半衰期长度近似值就行 右眼皮跳是什么意思 右眼皮跳的含义这两天右眼皮老是跳,跳得不是很明显,但是一天次数不少,看是什么症兆 右眼皮跳什么含义这几天不知道怎么了右眼皮有时候跳,会不会有什么事发生吖? 右眼皮跳是寓意什么. -Excuse me,how can I get to the museum? -Sorry,It's my __time to be here. A.one B.first C.once 一道关于碳14半衰期的问题,Living matter has a carbon-14 activity of about 16.0counts/min per gram of carbon.What is the age of an artifact for which the carbon-14 activity is 8.00counts/min per gram of carbon?The half-life of carbon-14 is 5 某化石中有10个碳14,10个碳12,假设碳14的半衰期是2000年,问化石是多少年的?计算过程要简单概述!