Usage note
上下可以表示方向，比如上下楼梯，也可以表示大约的数量。
Shàngxià kěyǐ biǎoshì fāngxiàng, bǐrú shàngxià lóutī, yě kěyǐ biǎoshì dàyuē de shùliàng.
Up and down can indicate direction, like going up and down stairs, and can also indicate an approximate quantity.
Context note
在学校里，我们上下楼梯时要小心，不要跑。
Zài xuéxiào lǐ, wǒmen shàngxià lóutī shí yào xiǎoxīn, bùyào pǎo.
At school, we need to be careful when going up and down stairs, and not run.
5 examples
他上下打量了我一下。
tā shàng xià dǎ liang le wǒ yí xià。
He looked me up and down.
这个房间的温度上下波动。
zhè ge fáng jiān de wēn dù shàng xià bō dòng。
The temperature in this room fluctuates up and down.
我们上下学要遵守交通规则。
wǒ men shàng xià xué yào zūn shǒu jiāo tōng guī zé。
We must obey traffic rules when going to and from school.
这本书有上下两册。
zhè běn shū yǒu shàng xià liǎng cè。
This book has two volumes, upper and lower.
他上下班都坐公交车。
tā shàng xià bān dōu zuò gōng jiāo chē。
He takes the bus to and from work.
5 mini stories
小明上下楼梯时总是扶着扶手。这样很安全。
xiǎo míng shàng xià lóu tī shí zǒng shì fú zhe fú shǒu。 zhè yàng hěn ān quán。
Xiao Ming always holds the handrail when going up and down stairs. This is very safe.
小红每天上下学都经过一个小公园。她喜欢那里的花。
xiǎo hóng měi tiān shàng xià xué dōu jīng guò yí gè xiǎo gōng yuán。 tā xǐ huan nà lǐ de huā。
Xiao Hong passes a small park every day on her way to and from school. She likes the flowers there.
小华在操场上上下跳动。他在做运动。
xiǎo huá zài cāo chǎng shàng shàng xià tiào dòng。 tā zài zuò yùn dòng。
Xiao Hua is jumping up and down on the playground. He is exercising.
小丽的书包上下颠簸。因为她在跑步。
xiǎo lì de shū bāo shàng xià diān bǒ。 yīn wèi tā zài pǎo bù。
Xiao Li's backpack is bouncing up and down. Because she is running.
小刚和爸爸一起上下搬东西。他们在整理房间。
xiǎo gāng hé bà ba yì qǐ shàng xià bān dōng xī。 tā men zài zhěng lǐ fáng jiān。
Xiao Gang and his dad are moving things up and down together. They are tidying up the room.
Mini dialogue
上下楼梯
A
我们上下楼梯要小心。
Wǒmen shàngxià lóutī yào xiǎoxīn.
We must be careful going up and down the stairs.
B
对，不能跑。
Duì, bù néng pǎo.
Right, we can't run.
上下关系
A
在学校里，老师和学生是上下关系吗？
Zài xuéxiào lǐ, lǎoshī hé xuésheng shì shàngxià guānxì ma?
In school, are teachers and students in a superior-subordinate relationship?
B
是的，老师是上级，学生是下级。
Shì de, lǎoshī shì shàngjí, xuésheng shì xiàjí.
Yes, teachers are superiors, students are subordinates.
Related words and contrasts
contrast
左右
zuǒyòu
left and right; about, approximately
上下 is up-down, 左右 is left-right; both can mean 'approximately'.
contrast
前后
qiánhòu
front and back; around (time)
Another pair of directions, used for time or position.
related
升降
shēngjiàng
rise and fall
Similar to 上下 when talking about going up and down.