What is the passage mainly about?

Sleep continues the work of learning by sorting and keeping what was studied. (The first and last paragraphs both say sleep finishes the work that studying started.)

How do the two groups in the study differ?

One group sleeps before the test and the other stays awake for the same number of hours. (The second paragraph states this difference directly; both groups learn the same list.)

Why can a short night hurt learning even when the total hours look almost normal?

Because the hours lost are the later ones, which do a different job from deep sleep. (The passage says late stages help skills and links between ideas, and that a short night removes exactly those hours.)

In the sentence about deep sleep, fix means:

make something stable so it holds (The sentence adds so they hold, showing that fix here means make stable rather than repair.)

What Sleep Does With Learning: Level 2 Reading Comprehension Questions

After a day of learning, the brain does not simply switch off at night. During sleep, it sorts through what happened and decides what to keep.

Researchers test this with a simple design. Two groups learn the same list of words. One group sleeps before the test; the other stays awake for the same number of hours. The sleep group almost always remembers more.

Different stages of sleep seem to do different jobs. Deep sleep, early in the night, helps fix facts and events so they hold. Later stages, closer to morning, appear to help with skills and with links between ideas. This is one reason a short night hurts learning even when the total hours look almost normal: the hours you lose are the late ones.

The practical advice is boring but reliable. Review the hard material in the evening, then sleep a full night. You cannot study while you sleep, but you can let sleep finish the work your study started.

Comprehension questions