Sometimes we use this expression to describe something that it is difficult to do and use it as a simile.

有时候我们用这个来明喻很难完成的某事。

As it is difficult to do two things at the same time, the marquis answered Mathilde with a vacant expression as though he were reciting a lesson.

由于很难同时做两件事，侯爵一脸茫然地回答玛蒂尔德，就像在背课文一样。