他请了一周假，现在正忙着补上落下的工作进度。

He took a week off and is now busy ___catching up with his work.

我们视频通话了两个小时，互相了解近况。

We video called for two hours ___catching up on what's new.

她加快脚步追赶前面走远的同学。

She walked faster, ___catching up with her classmates who were ahead.