as

conj. 因为；随着；虽然；依照；当…时

prep. 如同；当作；以…的身份

adv. 同样地；和…一样的

中文词源

as 如同

由古英语alswa 分化出来的两个单词as 和 also, 后在词义和语法上逐渐产生了变化。

as: as: [12] Ultimately, as is the same word as also. Old English alswā ‘in just this way’ was used in some contexts in which modern English would use as, and as it was weakly stressed in such contexts it gradually dwindled to als or ase and finally to as.
=> also
as (adv.): c. 1200, worn-down form of Old English alswa "quite so" (see also), fully established by c. 1400. Equivalent to so; any distinction in use is purely idiomatic. Related to German als "as, than," from Middle High German also. Phrase as well "just as much" is recorded from late 15c.; the phrase also can imply "as well as not," "as well as anything else." Interjection of incredulity as if! (i.e. "as if that really could happen") is attested from 1995, an exact duplication of Latin quasi.

1. 也就是说它前后呈现出一种一致的比较、对照关系。2. 即这种对照结果是：相应的，一致的，符合的，同时的，顺着的，顺应的，匹配的上的对照或比较。3. if / though (即使、纵然) => as if / as though. => 也就是说好像跟即使、纵然这种假设的情况一致、一样似的。

3. English has hurt me a thousand times, but I still regard it as my first love.: 英语伤我千百遍，我待英语如初恋。

4. A fellow doesn't last long on what he has done. He's got to keep on delivering as he goes along.--Carl Hubbell, Baseball Player: 靠过去完成的无法让人保有成功，必须在路上持续交出成绩。

5. The Koran recommends fasting as a penance before pilgrimages.: 《古兰经》劝告人们在朝圣前斋戒，以作为一种补赎。