At ten o’clock, all the scientists were in the lab. BY
All the scientists were in the lab by ten o’clock
We were at the dinner table when the phone rang. HAVING
The phone rang while/when we were having dinner.
In the lesson, I noticed that my friend was sleeping. DURING
I noticed that my friend was asleep during the lesson
He spoke to us after his meeting. BEFORE
He didn’t speak to us before his meeting.
They said the name of the winner and we immediately cheered. AS
We cheered as soon as they said the name of the winner.
She travelled after she graduated from university. UNTIL
She didn’t travel until she graduated from university.