他的行为未能达到我们的期望。

His behaviour ___falls ___short ___of what we expect.

她刚好未能达到她需要的成绩。

She just ___fell ___short ___of the grades she needed.

这种日常事务真的让我筋疲力尽，但我不想辜负父母的期望。

This routine was really wearing me out, but, I didn't want to ___fall ___short ___of my parents' expectations.