know

来自古英语cnawan,来自Proto-Germanic*knew,来自PIE*gno,知道，认识，理解，词源同can,ken,cognizance,narrate,notice.

know

know: [11] The words for ‘know’ in the various Indo-European languages mostly belong to one large many-branched family which goes back ultimately to the base *gn-, which also produced English can and ken. Its Latin offspring was nōscere, from which English gets cognition, incognito, note, quaint, etc. From its Greek branch come English agnostic and diagnosis.

And in other Indo-European languages it is represented by, among others, Sanskrit jānáti ‘know’, Old Irish gnáth ‘known’, and Russian znat’. In the other Germanic languages it is the immediate relatives of English can (German and Dutch kennen, Swedish känna, Danish kende) that are used for ‘know’; know itself, which was originally a reduplicated form, survives only in English.

The -ledge of knowledge [13] was probably originally the suffix -lock ‘action, process’, which otherwise survives only in wedlock. Acknowledge [15] is derived from knowledge.
=> agnostic, can, cognition, diagnosis, incognito, ken, knowledge, note, quaint, recognize

know (v.)

Old English cnawan (class VII strong verb; past tense cneow, past participle cnawen), "to know, perceive; acknowledge, declare," from Proto-Germanic *knew- (cognates: Old High German bi-chnaan, ir-chnaan "to know"), from PIE root *gno- "to know" (cognates: Old Persian xšnasatiy "he shall know;" Old Church Slavonic znati, Russian znat "to know;" Latin gnoscere; Greek *gno-, as in gignoskein; Sanskrit jna- "know"). Once widespread in Germanic, this form is now retained only in English, where however it has widespread application, covering meanings that require two or more verbs in other languages (such as German wissen, kennen, erkennen and in part können; French connaître, savoir; Latin novisse, cognoscere; Old Church Slavonic znaja, vemi). The Anglo-Saxons used two distinct words for this, witan (see wit) and cnawan.

Meaning "to have sexual intercourse with" is attested from c. 1200, from the Old Testament. To not know one's ass from one's elbow is from 1930. To know better "to have learned from experience" is from 1704. You know as a parenthetical filler is from 1712, but it has roots in 14c. To know too much (to be allowed to live, escape, etc.) is from 1872. As an expression of surprise, what do you know attested by 1914.

know (n.)

"inside information" (as in in the know), 1883; earlier "fact of knowing" (1590s), from know (v.).

1. I know it's nothing serious and I feel quite unemotional about it.

我知道那根本没什么大不了的，所以有些无动于衷。

2. We all know that fats spoil by becoming rancid.

我们都知道油脂变质后会发臭。

3. Kaspar had spoken know-ledgeably about the state of agriculture in Europe.

卡斯帕对欧洲农业状况发表了一番颇有见地的见解。

4. I know how to darn, and how to sew a button on.

我会打补丁，缝纽扣。

5. You have to know where to stand for a good viewpoint.

你得知道站在哪里观察角度比较理想。