才
cái
Expressing "only after" with "cai"
才 in the second clause means the result came only after the first thing happened.
Condition / Event，才 + Result
How it works
那本书我看了两遍才看懂 — I only understood that book after reading it twice.
It marks the result as hard-won or delayed, in contrast to 就, which would make it easy and immediate.
As always with 才, no 了 follows the verb it governs.
Examples
nà běn shū wǒ kàn le liǎng biàn cái kàn dǒng
那本书我看了两遍才看懂。
I only understood that book after reading it twice.
tā shuō le sān cì wǒ cái tīng qīng chǔ
他说了三次我才听清楚。
He had to say it three times before I caught it.
chī le yào cái hǎo yì diǎn
吃了药才好一点。
It only got better after I took the medicine.