或る時[arutoki] once (i.e. "once, when I was studying ..")
或る人[aruhito] someone (unspecified, but someone in particular)
或日[aruhi] one day (e.g. "one day while studying, ..")
或る[aru] a certain ...
或は[aruha] or

或る程度[aruteido] to some extent
或る種[arushu] certain
と或る[toaru] a certain ...
或る程度まで[aruteidomade] to some degree

御誕生日おめでとうございます[otanjoubiomedetougozaimasu] Happy Birthday
また明日[mataashita] see you tomorrow
旭日[kyokujitsu] rising sun
旭日昇天[kyokujitsushouten] full of vigor and vitality (like the rising sun) (vigour)
或日[aruhi] one day (e.g. "one day while studying, ..")

一日の長[ichijitsunochou] superiority
一日一日[ichinichiichinichi] gradually
一日一夜[ichinichiichiya] all day and night
一日増しに[ichinichimashini] day by day
一日置き[ichinichioki] every other day