警官在将罪犯押上巡逻车前给他戴上了手铐。

The officer was cuffing the criminal before putting him in the patrol car.

cuffing 是动词 cuff 的现在分词形式。cuff 本意是"袖口"，引申为"手铐"的意思，因为手铐戴在手腕处就像袖口一样。cuffing 在这里指"给某人戴上手铐"的动作。