This question presents a sentence, part of which or all of which is underlined. Beneath the sentence, you will find five ways of phrasing the underlined part. The first of these repeats the original; the other four are different. If you think the original is best, choose the first answer; otherwise, choose one of the others.
The students worked diligently together on their project until they are too tired to work any longer, then they took a brief break to rest before tackling the project again, because it is due the following morning.