请用LINGOES词典关注lose（lost）以及fix的各种用法.
Her eyes were fixed on the gun.她紧盯着那枝枪.
fix sth on sb/sth = direct (esp. one's eyes) on sb/sth with steady attention
全神贯注於,（尤指）凝视某人[某物]
My sister sat silent for some time, lost in thought.
我姐姐沉默地坐了一会儿,陷入沉思.
She heaved a sigh and became lost in thought.
她叹了口气,随即陷入了沉思.