当他们开始谈论哲学时，我完全感到力不从心。

When they start talking about philosophy, I'm completely ___out ___of ___my ___depth.

在他工作的第一天，他感到水深火热。

On his first day at work, he felt ___out ___of ___his ___depth.

当讨论量子物理时，她感到力不从心。

She was ___out ___of ___her ___depth when discussing quantum physics.