我的目光一直凝视着他的脸。

I kept my eyes ___fixed on his face.

他的眼睛凝视着遥远的地平线，陷入了沉思。

His eyes were ___fixed on the distant horizon, lost in thought.

她凝视的目光暴露了她对那个问题的全神贯注。

Her ___fixed gaze betrayed her intense concentration on the problem.