"sit up" in Chinese (Simplified)
坐起来仰卧起坐（锻炼）
Definition
从躺着或弯腰姿势变为直立坐着。也指一种仰卧起坐的锻炼方式，从平躺状态抬起上半身。
Usage Notes (Chinese (Simplified))
常用于要求某人坐正或注意。作名词时“sit-up”专指仰卧起坐的锻炼。不要与“stay up”（保持清醒）混淆。
Examples
Please sit up straight in your chair.
请在椅子上**坐起来**，坐直。
She told the children to sit up and listen.
她让孩子们**坐起来**听讲。
Can you do ten sit-ups every morning?
你每天早上能做十个**仰卧起坐**吗？
He had to sit up suddenly when he heard the noise.
他听到声音时突然**坐起来**。
After lying down for hours, it was hard for her to sit up.
躺了几个小时后，她很难**坐起来**。
He does a hundred sit-ups before breakfast every day.
他每天早餐前做一百个**仰卧起坐**。