他说得如此快以至我不能跟上他。

He spoke so quickly that I couldn't follow him.

youdao

我将要退出游泳，因为我不能跟上游泳课。

I'll quit swimming because I can't catch up with the class.

youdao

更糟的是，我不能跟上我所有的朋友所使用的全部程序。

And what's worse, I can't keep track of all the applications that all of my friends are using.

youdao