He used to sit up late studying.

他过去经常学习到深夜。

I never sit up late in the night.

我从来不会在晚上的时候迟睡。

We don't allow the children to sit up late.

我们不允许孩子们熬夜。

It's not right for children to sit up late .

让迟到的孩子罚站是不对的。

The doctor warned his patient not to sit up late at night.

医生告诫他的病人晚上不要熬夜。