They had to sit up all night to prepare for the exam.
sit up late
Frequency:
60
%
She had to sit up late to finish her assignment.
sit up and take notice
Frequency:
50
%
The new evidence made everyone sit up and take notice.
Idiomatic Expressions for sit up
Phrase: sit up straight
Meaning: to sit with a straight posture, usually to appear attentive or respectful
Usage: During the meeting, it's important to sit up straight and show that you are engaged.