鋁合金抗彎

___you able to float on your back? have been study 为什么不说have studied ,have been absent 为什么不说have absented1 have been study 和 have been absent最常见到,既然不是被动语态（主语是人）,为什么不直接用have + 动词过去分词的形式呢?2 have 英文课本里的一句话,不太明白语法,He had theories about almost any subject under the sun ,including vegetarianism ,the drama,politics,and music; and in support of these theories he wrote pamphlets,letters,books…thousands upon thousands 甲乙两种废液,甲含硫酸和硫酸镁,已含氢氧化钠溶液通过处理得到中性溶液并得到固体硫酸镁不添加其他试液 fun的过去式是什么?不要过去分词. Until You 怎么读 make fun of的过去式? Until you怎么读拼音代替 dhl是哪个国家的 CFI DHL EJ（ ） Where is Bill?He ______.A.at home B.at school C.is reading in bed D.read in bed..说明原因. regret有不及物动词形式吗?我知道有及物动词形式,但是否也能当不及物动词用呢?比如：you'll regret... 有一块如图所示的平行四边草坪如果要在它的四周种上鲜花,则需种鲜花的总长度是多少?第一个数字20米,它右边的数字30米,最下面的数字45米! 英语中能加doing的动词如allow或regret等等,它们都能将doing的形式变成having done构成v.+having done的形式吗?如果不能,请给几个常用的典例, 在我们草坪里的花,谁知道叫什么? 英语七上题my sister's favorite food is mapo tofu的同义句 my sister _____mapo tofu _____my sister's favorite food is mapo tofu的同义句 my sister _____mapo tofu _____.how boring the film is!的同义句_____ _____ _____film it is!they had 花有一共多少种 the children are school and the parents are work 花一共有多少种? The football on the floor is Tom's.Tom's parents are ___ work. 已知a在第二象限,如何判断sin(cosa)的符号 花有多少种颜色 Today it is very cold and the temperature is eiToday it is very cold and the temperature is eight zero 请问这四种分别是什么花 这4种分别是什么花?如图. 这4种分别是什么花?如图. 高龄产妇的具体定义是什么,34岁怀孕,35岁生, 岁午生世, 以为己生岁直子,鼠,子神也(中的通假字)今天就要 在The temperature outside is two degrees中,为何outside放在temperature的后面 这人说的话听起来很粗鲁（汉译英） ——the man said sounds rude.只说正确的英语是不够的（汉译英）——correct English only isn't enough.当于不同的人交谈时,我们改变说话的方式.（汉译英）When ____wi custom 和customer当顾客讲时的区别是什么?字典上说custom是总称,