Dolphins sleep with one eye open.

海豚睡觉睁一眼闭一眼。

Dolphins sleep with one eye open.

海豚睡觉，睁一只眼闭一只眼。

You have to sleep with one eye open for the rest of your life.

你的余生都将睁着一只眼睛睡觉。

You are looking into the unblinking eyes of elephants, who sleep with one eye open.

你正看在看得是猫头鹰一眨不眨的眼，它们睡觉时只闭一只眼睛。

Most of the time, when you do sleep, you sleep with one eye open for fear of having something stolen, or being attacked.

大部分睡觉时，都是一只眼睁着，提防被偷或者被袭击，而闭着另一只眼。