他换工作太频繁了，我都跟不上了。

He changes jobs so frequently that I can't ___keep ___track anymore.

务必跟踪时间，以免迟到。

Be sure to ___keep ___track of the time to avoid being late.

跟踪技术的所有快速变化很困难。

It's difficult to ___keep ___track of all the rapid changes in technology.