Using "cai" for small numbers

The character 才 (cái) can be used to emphasize that a number is small, or less than expected.

Used as a Verb

In this case, 才 means "is only" or "only have."

才 + Number + [Measure Word] + Noun

In English, we often express this by using "only" or "just" to emphasize that the number is small.

你才二十岁？Nǐ cái èrshí suì?You're only twenty?
这个班才两个学生。 Zhège bān cái liǎng gè xuéshēng.This class only has two students.
你的工资才两千？Probably RMB, per monthNǐ de gōngzī cái liǎng qiān?Your salary is only two thousand?
这顿饭才二十块，太便宜了！Zhè dùn fàn cái èrshí kuài. Tài piányi le!This meal only cost twenty kuai. It's too cheap!
你才一百斤，还要减肥？One "jin" = 500gNǐ cái yī bǎi jīn, hái yào jiǎnféi?You're only 100 jin and you still want to lose some weight?

才 + Verb + Number + Measure Word + Noun

In this pattern, adding a 了 after the verb is optional.

她才来了两个月。Tā cái lái le liǎng gè yuè.She's been here for only two months.
这家店关门了？可是它才开业一个星期。Zhè jiā diàn guānmén le? Kěshì tā cái kāiyè yī gè xīngqī.This shop is out of business? But it's only been one week since it opened.
已经两天了，你才看完一页？Yǐjīng liǎng tiān le, nǐ cái kàn wán yī yè?It's been two days and you only finished reading one page?
我们才玩了一会儿，再玩一会儿吧？Wǒmen cái wán le yīhuìr, zài wán yīhuìr ba?We've only played for a short while. Can we play a little bit longer?
他们结婚了？他们才认识三个月！Tāmen jiéhūn le? Tāmen cái rènshi sān gè yuè!They got married? They've only known each other for three months!