to move your eyebrows close together in an expression that shows you are feeling worried or serious, or are thinking carefully about something 皺眉(表示擔憂、嚴肅或認真思考)
[I/T]if your face or a part of it sets into a particular expression, or if you set it into a particular expression, you have that expression on your face (使)(臉上)凝固(某種表情)
His face set into a determined expression as he read the letter. 他看信的時候神色堅毅。