是⋯⋯的
shì …… de
The "shi… de" construction for emphasising details
When everyone already knows an action happened, 是…的 asks about or highlights the how, when or where of it.
Subj. + 是 + [detail] + Verb + 的
How it works
你是怎么来的? — we both know you arrived; what I want is the method. Compare 你怎么来? which asks about a future trip.
The 是 goes in front of the detail being highlighted and 的 goes at the end, usually after the verb: 我是坐飞机来的, 他是昨天到的.
In casual speech the 是 is often dropped in statements, but the 的 stays: 我昨天来的.
Examples
nǐ shì zěn me lái de?
你是怎么来的？
How did you get here?
wǒ shì zuò fēi jī lái de
我是坐飞机来的。
I came by plane.
tā shì zuó tiān dào de
他是昨天到的。
He arrived yesterday.