直到⋯⋯才⋯⋯
zhí dào …… cái ……
Expressing "all the way until" with "zhidao"
直到…才… means nothing happened until that point.
直到 + Time / Event，Subj. + 才 + Verb
How it works
直到十二点半，我才做完作业 — I didn't finish my homework until half past twelve.
The 才 in the second half is what carries "not until", so it can't be dropped.
直到 can also end a stretch: 我一直等到他回来.
Examples
zhí dào shí èr diǎn bàn, wǒ cái zuò wán zuò yè
直到十二点半，我才做完作业。
I didn't finish my homework until half twelve.
zhí dào zuó tiān wǒ cái zhī dào zhè jiàn shì
直到昨天我才知道这件事。
I only found out about this yesterday.
tā zhí dào sān shí suì cái jié hūn
他直到三十岁才结婚。
He didn't marry until he was thirty.