puzzle over
Upper Intermediate (B2)neutral
To keep thinking about something because you can't understand it or find the answer.
"Scientists have puzzled over this strange phenomenon for decades."
Hear it in context

The First, Second, and Third Crusades: 1095-1192 | MEGA-COMPILATION DOCUMENTARY
Real Crusades History · 225:17
dying historians today still puzzle over the mystery

After YEARS of Work… Turbo R32 Finally Looks Like a Car Again
HumbleMechanic · 21:29
We have one other piece of the puzzle over here

Roman Yampolskiy Testifying for UK Parliament/Human Rights Committee.
Roman Yampolskiy · 34:04
So we will puzzle over what you have to say.

Sunrise on the Reaping A Hunger Games Novel By Suzanne Collins AudioBook P1
AudioBookEng · 89:07
As I puzzle over how we might achieve this, Plutarch reappears