我太累了，无法清晰思考。

I was so tired that I could ___not ___think ___straight.

我的压力让我无法清晰思考。

My stress would ___not let me ___think ___straight.

当我焦虑时，我根本无法清晰思考。

When I'm anxious, I simply can ___not ___think ___straight.