sit (someone) up
phrasal verb with sit verb uk/sɪt/ us/sɪt/ sitting | sat
（使）坐起来；（帮某人）坐起来
to move into a sitting position after you have been lying down, or to help someone else to do this
Let me sit you up in the bed so you'll be more comfortable. 我帮你从床上坐起来吧，这样你会更舒服些。