The character 才 (cái) is one of those very common parts of Chinese grammar that many students find difficult because it is so common and versatile. Here we’ll separate the grammatical uses of 才 into four different types and look at it that way.
才 meaning “only”
才 can mean “only”, i.e. it implies that something is small or few in quantity. When used in this way, it very often appears with a measure word and a number. In this way it can express that “there are only x things”.
Have a look at an example:
A: 你怎么有那么多？
Nǐ zěnme yǒu nàme duō?
How come you've got so many?
B: 我才有两个！
Wǒ cái yǒu liǎng gè!
I've only got two!
We don’t know what these two people are talking about, but A seems to believe that B has a lot of it. B uses 才 to indicate that they don’t actually have a lot - they only have two.
Some more examples:
Notice how in all of these examples there is a sense of a sequence. Maybe in the future there will be more, but at the moment we’ve only reached a particular amount or number.
才 meaning “not until”
The next meaning of 才 we’ll look at is “not until”. This is also very common. When used in this way, 才 is always followed by a verb or verb phrase. Another thing to note is that when 才 means “not until”, it usually means that the event is expected or anticipated.
Some examples:
Always remember that when using 才 to talk about timings, you don’t use 了. The two characters 才 and 了 don’t generally play well together; it’s one or the other.
Another little tip that you might find useful is that when 才 is used with times, you could think of it as being the opposite of ‘already’. ‘Already’ can suggest that something happened earlier than expected, whereas 才 can suggest that it happened later than expected.
As well as talking about actual times, 才 can be used a little more idiomatically to talk about whether things qualify or meet certain standards. Some examples should make this idea clearer:
As you can see, it’s not totally clear if this use of 才 is closer to “only” or “not until”. Hopefully it demonstrates how all these uses of 才 are related. They’re all have something to do with meeting certain levels or certain lines being crossed.
If you’ve seen this clip from the film Crocodile Dundee, you might be able to get a good sense of using 才 in this way. In the scene, Crocodile Dundee is not impressed by the knife a mugger is trying to threaten him with. He pulls out his own much larger knife and says “This is a knife.” In Chinese, you could use 才 in that situation:
We don’t recommend that you go round carrying knives or trying to use them, though! Also, it’s a shame that, like a lot of Hollywood films, the clip seems to have an unpleasant racial message - why do they always have to ruin films by doing that?
Finally, you might enjoy this silly cartoon demonstrating a (rather rude!) use of 才:
Source
Bonus points to whoever can translate and explain the cartoon in the comments!
才 meaning “just now”
A lot of textbooks separate this meaning of 才 from the others. In our view though, it’s actually just a subset of 才 meaning “not until”. When used to mean “just now”, or “a moment ago”, 才 nearly always implies that the event should have happened earlier. I.e., it’s usually saying “it didn’t happen until just now”. Therefore it’s just a subset of 才 meaning “not until”, in our view.
Some examples:
These all mean “just now” or “a moment ago”, but there’s clearly a sense of “only just now” as well. It feels as if the events were expected to happen sooner, but didn’t.
才 for emphasis
Finally, 才 can be used to add strong emphasis to a sentence. We know that “emphasis” is often used as a default explanation for many things when learning languages, but unfortunately in a lot of cases it is the best explanation! 才 really is just adding heavy emphasis in these sentences:
Notice how this use of 才 is combined with 呢 to really ramp up the emphasis.