They had to work ______ so that they could finish work on time.
Understand the Problem
The question is asking to choose the correct word to fill in the blank in the sentence, focusing on the context of working hours.
Answer
so that
The correct answer is 'so that'.
Answer for screen readers
The correct answer is 'so that'.
More Information
The conjunction 'so that' is used to show purpose, indicating why they worked overtime.