Usage note
“要不然”表示如果不这样做，就会发生别的情况。
“Yàobùrán” biǎoshì rúguǒ bù zhèyàng zuò, jiù huì fāshēng bié de qíngkuàng.
"Otherwise" indicates that if you don't do this, something else will happen.
Context note
小朋友要按时完成作业，要不然老师会担心。
Xiǎo péngyǒu yào ànshí wánchéng zuòyè, yàobùrán lǎoshī huì dānxīn.
Children should finish homework on time, otherwise the teacher will worry.
5 examples
快穿上外套，要不然会感冒。
kuài chuān shàng wài tào， yào bù rán huì gǎn mào。
Put on your coat quickly, otherwise you'll catch a cold.
早点睡觉，要不然明天起不来。
zǎo diǎn shuì jiào， yào bù rán míng tiān qǐ bù lái。
Go to bed early, otherwise you won't wake up tomorrow.
带伞吧，要不然下雨会淋湿。
dài sǎn ba， yào bù rán xià yǔ huì lín shī。
Take an umbrella, otherwise you'll get wet in the rain.
认真听讲，要不然不会做题。
rèn zhēn tīng jiǎng， yào bù rán bú huì zuò tí。
Listen carefully in class, otherwise you won't know how to solve problems.
我们一起玩，要不然一个人很无聊。
wǒ men yì qǐ wán， yào bù rán yí gè rén hěn wú liáo。
Let's play together, otherwise it's boring alone.
5 mini stories
小华忘记带水壶，要不然他可以喝水。他只好去接水。
xiǎo huá wàng jì dài shuǐ hú， yào bù rán tā kě yǐ hē shuǐ。 tā zhǐ hǎo qù jiē shuǐ。
Xiao Hua forgot to bring his water bottle, otherwise he could drink water. He had to get water instead.
小丽每天练字，要不然字会写不好。她写得很漂亮。
xiǎo lì měi tiān liàn zì， yào bù rán zì huì xiě bù hǎo。 tā xiě dé hěn piào liang。
Xiao Li practices writing every day, otherwise her handwriting would be poor. She writes beautifully.
我们要排队，要不然会乱。大家都很守秩序。
wǒ men yào pái duì， yào bù rán huì luàn。 dà jiā dōu hěn shǒu zhì xù。
We need to line up, otherwise it will be chaotic. Everyone follows the order.
小明先做作业，要不然妈妈会生气。他很快就完成了。
xiǎo míng xiān zuò zuò yè， yào bù rán mā ma huì shēng qì。 tā hěn kuài jiù wán chéng le。
Xiao Ming does homework first, otherwise mom will be angry. He finished quickly.
下雨了，快回家，要不然会淋湿。他们跑进屋里。
xià yǔ le， kuài huí jiā， yào bù rán huì lín shī。 tā men pǎo jìn wū lǐ。
It's raining, go home quickly, otherwise you'll get wet. They ran into the house.
Mini dialogue
快起床
A
快起床，要不然你会迟到。
Kuài qǐchuáng, yàobùrán nǐ huì chídào.
Get up quickly, otherwise you'll be late.
B
好的，我马上起来。
Hǎo de, wǒ mǎshàng qǐlái.
Okay, I'll get up right away.
带伞
A
外面可能要下雨，你带伞吧，要不然会淋湿。
Wàimiàn kěnéng yào xià yǔ, nǐ dài sǎn ba, yàobùrán huì lín shī.
It might rain outside, take an umbrella, otherwise you'll get wet.
B
谢谢提醒，我这就带。
Xièxie tíxǐng, wǒ zhè jiù dài.
Thanks for reminding me, I'll take it now.
Related words and contrasts
similar
否则
fǒuzé
otherwise
Used in formal contexts
similar
不然
bùrán
otherwise
Common in spoken Chinese