Subject + 睁开 + 眼睛/双眼
睁开 (zhēngkāi) means "to open one's eyes." The directional complement 开 indicates the separating or opening movement, and this verb is specifically used with eyes, as in 睁开双眼 (to open both eyes).
他慢慢睁开眼睛,发现自己在医院里。
Tā mànmàn zhēngkāi yǎnjīng, fāxiàn zìjǐ zài yīyuàn lǐ.
He slowly opened his eyes and found himself in a hospital.
早上闹钟一响,我就睁开了眼睛。
Zǎoshang nàozhōng yī xiǎng, wǒ jiù zhēngkāile yǎnjīng.
As soon as the alarm went off in the morning, I opened my eyes.
孩子睁开双眼,好奇地看着周围。
Háizi zhēngkāi shuāngyǎn, hàoqí de kànzhe zhōuwéi.
The child opened both eyes and looked around curiously.