Non-slippage rolling of a rigid body is a difficulty of teaching of geostatics.

刚体无滑滚动的问题是刚体力学的一个教学难点。

youdao

Chinese characters teaching to foreigners is the difficulty of teaching Chinese as a foreign language, of which the current situation is not satisfactory.

汉字教学是对外汉语教学的难点，汉字教学的现状不尽人意。

youdao

Process synchronization is an emphasis and difficulty in the teaching of operating system course.

在操作系统课程的教学中，进程同步是其中一个重点，也是难点。

youdao

For all the difficulty of doing a rigorous evaluation in order to improve teaching performance across the board, I suspect it is a whole lot easier to identify the worst teachers in the school.

FORBES: Getting Rid of Bad Teachers