Questions 17 to 20 are based on the following passage. At the end of the passage, you will be given 20 seconds to answer the questions. Now, listen to the passage. According to the passage, a good student in college must______.
A．go to every class, no matter how he or she feels B．go to class unless there is a good reason not to C．stay in the dormitory and study D．make excuses to the teacher