Almost everyday, I do sit-ups before going to sleep.
Doing sit-ups is an effective way to exercise abdominal muscles.
【Sit-ups】Sit-ups are exercises that you do to strengthen your stomach muscles. They involve sitting up from a lying position while keeping your legs
straight on the floor. / an stomach exercise in which a person sits up from a supine position without using the arms for leverage 仰卧起坐
He does 100 sit-ups each day.
由sit和up这两个单词组成的短语 sit up 都有些什么意思呢？
1.PHRASAL VERB If you sit up, you do not go to bed although it is very late. 熬夜
We sat up drinking and talking.
同义词组：break night / stay up late
2. PHRASAL VERB If you sit up, you move into a sitting position when you have been leaning back or lying down. 坐起来; 坐直身子
Her head spins dizzily as soon as she sits up.
I see nothing today. I cannot sit up to look out of the window.
The patient was but poorly able to sit up.
3. PHRASAL VERB If you sit someone up, you move them into a sitting position when they have been leaning back or lying down. 使坐起来
She sat him up and made him comfortable.