一日 jat¹ jat⁶ {yī rì}

(n.) a day or one day; (slang) used as part of a prepositional phrase (一日都係) to blame someone (or something or 'a reason') for some negative things that have happened, all because of; owing to; thanks to (e.g. 一日都係你 means "It's all because of you" or "Thanks to you".)

一日到黑 jat¹ jat⁶ dou³ hak¹ {yī rì dào hēi}

all day long

一日千里 jat¹ jat⁶ cin¹ lei⁵ {yī rì qiān lǐ}

lit. one day, a thousand miles (idiom); rapid progress

一日三餐 jat¹ jat⁶ saam¹ caan¹ {yī rì sān cān}

to have three meals a day

一日三秋 jat¹ jat⁶ saam¹ cau¹ {yī rì sān qiū}

a single day apart seems like three seasons (idiom)

一日之雅 jat¹ jat⁶ zi¹ ngaa⁵ {yī rì zhī yǎ}

1. lit. friends for a day (idiom)
2. fig. casual acquaintance

一日之計在於晨〔---计-于-〕 jat¹ jat⁶ zi¹ gai³ zoi⁶ jyu¹ san⁴ {yī rì zhī jì zài yú chén}

1. make your day's plan early in the morning (idiom)
2. early morning is the golden time of the day

一日不見，如隔三秋〔---见-----〕 jat¹ jat⁶ bat¹ gin³ ，jyu⁴ gaak³ saam¹ cau¹ {yī rì bù jiàn , rú gé sān qiū}

one day apart seems like three years (idiom)

一日為師，終身為父〔--为师-终-为-〕 jat¹ jat⁶ wai⁴ si¹ ，zung¹ san¹ wai⁴ fu⁶ {yī rì wéi shī , zhōng shēn wéi fù}

lit. teacher for one day, father for ever (idiom)