Stephen, can you work overtime tonight?
What's wrong? We have been working overtime recently.
The holiday is coming so we need to finish our task.
Must we finish our task before the holiday?
Yes. The contract must be kept.
OK. I know. But Bob wanted to change shifts with me tonight.
Did he say why?
He said he would celebrate his girlfriend's birthday.
Don't worry. I will tell him about that.
It is convenient for me to work overtime tonight.