或……，或……: either… or… (listing possibilities)
【高102】复句 / complex sentences (选择)
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
或 A，或 B (written) lists open possibilities without forcing a choice: “now A, now B”, “either A or B”. A and B are short phrases of the same kind (places, numbers, actions), and the series can go on (，或 C). It describes cases that happen or may happen: 周末，大家或在家看书，或出门散步.
The repeated 或 keeps its classical sense “in one case, in another”. In 《师说》 Han Yu writes 句读之不知，惑之不解，或师焉，或不焉: each 或 opens one case, a teacher is taken for the first (句读, knowing how to punctuate, the basics) but not for the second (惑, one's own doubts).
Do not confuse it with 要么……要么…… (hsk5-g33), which forces a choice between the two, or with 不是……就是…… (hsk3-g68), which states that it is surely one of the two. To ask a question, keep 还是 (你喝茶还是喝咖啡？); 或者 links two options in a statement (你或者我去都行) without being repeated.
Examples
周末，大家或在家看书，或出门散步，或约朋友喝茶。
Zhōumò, dàjiā huò zài jiā kànshū, huò chūmén sànbù, huò yuē péngyou hē chá.At the weekend people either read at home, or go out for a walk, or meet friends for tea.
假期里，同学们或回老家陪父母，或留在学校做研究，各有各的安排。
Jiàqī lǐ, tóngxuémen huò huí lǎojiā péi fùmǔ, huò liú zài xuéxiào zuò yánjiū, gè yǒu gè de ānpái.In the holidays the students either go home to be with their parents or stay at the university to do research: everyone has their own plans.
他把信藏在某个秘密的地方了，或一块石头下面，或一棵树后面。
Tā bǎ xìn cáng zài mǒu ge mìmì de dìfang le, huò yí kuài shítou xiàmiàn, huò yì kē shù hòumiàn.He has hidden the letter in some secret place, under a stone or behind a tree.
阿姨每次来我家都带着一群朋友，或二三人，或三四人。
Āyí měi cì lái wǒ jiā dōu dàizhe yì qún péngyou, huò èr sān rén, huò sān sì rén.Every time my aunt comes to our house she brings a group of friends, two or three people, or three or four.
句读之不知，惑之不解，或师焉，或不焉。
Jùdòu zhī bù zhī, huò zhī bù jiě, huò shī yān, huò fǒu yān.Not knowing how to punctuate, not resolving one's doubts: in one case a teacher is taken, in the other not. (Han Yu, 《师说》)
Common mistakes
✗ 你喝茶或喝咖啡？ → ✓ 你喝茶还是喝咖啡？ (in a question you use 还是).
✗ 你或去，或不去，快决定！ → ✓ 你要么去，要么不去，快决定！ (to force a choice you need 要么……要么……).