[originaltext]Sleep expert David Earnest often tells college students that a go

Sleep expert David Earnest often tells college students that a good night’s sleep is important for academic success. Not that they listen to him. Earnest is a professor at Texas A&M College of Medicine. He explains that so-called “all nighters,” in which students spend all night studying instead of sleeping, are not effective-or healthy. “The sort of common approach for college students is to wait until the last minute in terms of preparing or studying for an exam, especially before final exams. Because that way, you can cram all of your studying into a very short period of time. But in the process obviously that compromises sleep and unfortunately it’s counterproductive.”
College students often wait until the last minute to review information and study for an exam. They may stay up all night ahead of the test.
Research shows, however, it is not worth it. Earnest explains that people who stay up all night do not remember as much about what they read or studied. There is also some evidence that people even suffer temporary drops in their IQ, or intelligence quotient, he said. If a student must prepare for an exam at the last minute,
Earnest suggests studying until about 2 am, sleeping for four hours, and then reviewing the material again early in the morning. Four hours is not enough sleep, but it is better than no sleep, Earnest said.
Questions 19 to 21 are based on the passage you have just heard.
19. What can we learn about David Earnest?
20. What is students’ common method of preparing for an exam?
21. What does David Earnest say about staying up?