If your friend cannot stop talking about something because she thinks it is important, you might say she has a bee in her bonnet.

VOA: special.2009.06.28

I cannot stop.

我停不下来

耶鲁公开课 - 基础物理课程节选

We are going to have to stop doing that because we cannot find an individual electron.

我们正要停止那么做,因为无法发现一个独立电子。

麻省理工公开课 - 固态化学导论课程节选

Ready to go! Fired up! Ready to go! They cannot stop us.

VOA: standard.2009.09.12

"We cannot stop terrorism or defeat the ideologies of violent extremism when hundreds of millions of young people see a future with no jobs,no hope and no way ever to catch up to the developed world,"

VOA: standard.2010.01.06