In Chinese, there are phrases that follow the 一A一B pattern. These are idiomatic, fixed expressions that just need to be memorized.
In the construction, we should one-syllable words in place of “A” and “B”
Let’s learn the most popular expressions:
一五一十 一针一线 一模一样 一唱一和 一张一弛 一时一刻
He explained to me in detail what I had to do
tā yí wǔ yì shí de gěi wǒ jiěshì le wǒ yào zěnme zuò