Subject + 拍 + 了 + 拍 + Object
拍 (pāi) means "to pat" or "to slap lightly," describing a gentle striking motion with the hand. It is often used in descriptions of friendly or comforting gestures, such as 拍了拍他的肩膀 (patted him on the shoulder).
她轻轻拍了拍孩子的背,哄他入睡。
Tā qīngqīng pāi le pāi háizi de bèi, hǒng tā rùshuì.
She gently patted the child's back to lull him to sleep.
他拍了拍裤子上的灰就站了起来。
Tā pāi le pāi kùzi shàng de huī jiù zhàn le qǐlái.
He patted the dust off his pants and stood up.
别拍桌子,吓到我了。
Bié pāi zhuōzi, xià dào wǒ le.
Don't slam the table — you scared me.