15.Q: What does the woman think the man should also do?
A. Lose weight.
B. Quit smoking.
C. Weigh himself frequently.
D. Have a talk with the doctor.
16. Q: What are the man and the woman talking about?
A. Registering for courses.
B. Buying a new computer.
C. Getting directions.
D. Studying sociology.
15. M: The doctor said if I kepting smoking, I would increase my chances of having a heart attack.
W: Did he suggest reducing weight, too?
16. M: The deadline for the sociology and computer courses is the day after tomorrow.
M: But I haven't decided which courses to take yet.
16.A。解析：根据"Which courses to take 选什么课程"，可以知道他们在讨论选课的问题。答案为A。