Either… or…: 不是……就是
复句 / complex sentences
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
Subject + 不是 + A，就是 + B
不是A，就是B = "if it's not A, it's B" → "either A or B". You present the only two possibilities, often to describe a habit (sometimes with a complaining tone).
他周末不是睡觉，就是玩游戏 (at weekends he either sleeps or plays video games).
⚠️ Don't confuse it with 不是A，而是B (it's not A, it's B): here, A is still possible!
Examples
我的工资不是交房租，就是还信用卡。
Wǒ de gōngzī bú shì jiāo fángzū, jiù shì huán xìnyòngkǎ.My salary goes either on rent or on paying off my credit card.
他每天不是在银行，就是在去银行的路上。
Tā měi tiān bú shì zài yínháng, jiù shì zài qù yínháng de lù shang.Every day he's either at the bank or on his way there.
周末我不是在家做饭，就是去超市买东西。
Zhōumò wǒ bú shì zài jiā zuòfàn, jiù shì qù chāoshì mǎi dōngxi.At weekends I either cook at home or go shopping at the supermarket.
Common mistakes
✗ 不是……而是…… for "either… or…" → ✓ 不是……就是……
✗ 不是……还是…… → ✓ 不是……就是……