The normal rules of plurals and articles apply, except that it's convention to write "an other" as one word. When 'other' is a noun: Singular indefinite - Another (an otherl Singular definite - The other Plural indefinite - Others Plural definite - The others When 'other' is an adjective: Singular indefinite - Another day (an other day) Singular definite - The other day Plural indefinite - Other days Plural definite - The other days

we can learn languae together^^

Sorry, that was a typo.

I understand ,

It's "ON the one hand" or "ON one hand". It can never be "ONE (the) one hand".