The boy puzzled his way through geometry.

那男孩煞费苦心地钻研几何学。

The book was the result of ten years’ assiduous research.

那本年苦心钻研的成果。

The professor's erudition came from long years of study.

这位教授的学问来自长年累月的钻研。

Marjorie and Heather spent hours poring over cookery books.

马里和希瑟花了几小时的时间钻研烹调。

The professor is hammering at an economic problem.

教授正在钻研一学问题。