dragonyanyan
如下：
火线：用L代表，是英文Live的缩写。
零线：用N代表，是英文Null的缩写，也有称为中性线的，英文为：Neutral。
地线：用E代表,是英文Earth的缩写。
火线简介：
火线一般是黄色绿色红色，在动力电缆中黄色绿色红色分别代表A相B相C相（三相火线）蓝色代表零线，黄绿双色代表接地线。用L字母表示。
照明电路里的两根电线，一根叫火线，另一根则叫零线。火线和零线的区别在于它们对地的电压不同：火线对地电压为220V；零线的对地的电压等于零（它本身跟大地相连接在一起的）。
所以当人的一部分碰上了火线，另一部分站在地上，人的这两个部分之间的电压等于220V，就有触电的危险了。反之人即使用手去抓零线，如果人是站在地上的话，由于零线的对地的电压等于零，所以人的身体各部分之间的电压等于零，人就没有触电的危险。
以上内容参考：百度百科-火线；百度百科-零线
纳兰依若
The connection,connect, link, joint,concatenate。
连接的短语有:连接 Connection;Join;Link
紧密连接 Tight junction;zonulae occludens;
TJs连接形式 Connecting format;Type of connection;Connect the form
作文中常用连接词的选择 表示强调的连接词 still, Indeed, apparently, oddly enough, of course, after all, significantly, interestingly, also, above all, surely, certainly, undoubtedly, in any case, anyway, above all, in fact, especially. Obviously, clearly.
表示比较的连接词 like, similarly, likewise, in the same way, in the same manner, equally.
表示对比的连接词 by contrast, on the contrary, while, whereas, on the other hand, unlike, instead, but, conversely, different from, however, nevertheless, otherwise, whereas, unlike, yet, in contrast.
表示列举的连接词 for example, for instance, such as, take ...for example. Except (for), to illustrate.
表示时间的连接词 later, next, then, finally, at last, eventually, meanwhile, from now on, at the same time, for the time being, in the end, immediately, in the meantime, in the meanwhile, recently, soon, now and then, during, nowadays, since, lately, as soon as, afterwards, temporarily, earlier, now, after a while.
表示顺序的连接词 first, second, third, then, finally, to begin with, first of all。
