A、Nausea. B、Fever. C、A cold. D、Diarrhea. D从“You are suffering from diarrhea．”可知。

M: I feel an abdominal pain and nausea.
W: Do you feel like vomiting?
M: Yes. I also have a slight fever.
W: How about your bowel movement?
M: Since this morning, I have been passing loose, watery stools several times.
W: You are suffering from diarrhea. What did you eat yesterday?
M: I ate some staled bread and other food.
W: The food might have been contaminated with bacteria.
M: Can I eat or drink anything?
W: You should drink a lot of water and fruit juice but do not eat for a day so that your bowels will have a rest. If you eat, take small servings of soft bland food, such as porridge cereal. Avoid large meals.
M: Should I take medication?
W: If your diarrhea is so frequent or watery as to cause inconvenience, you can take some medicines as prescribed by the doctor.
M: Is diarrhea serious?
W: Yes, only when you get dehydrated or lose much body fluids. So you should drink freely to replace the salt and water.
M: What are the signs of dehydration?
W: The signs of dehydration are inelastic skin, dry lips and mouth, thirst tongue. If you pitch up the skin on your arm or abdomen and let it go, it sets back slowly.
M: Do I have to go to the clinic?
W: If your diarrhea persists for three or four days, you should go to the doctor especially when the stool is black and bloody. In your present case, you don’t have to worry. Just take some medicine and replace for lost fluid.
Questions 16-20 are based on the conversation you have just heard.
16. What is the woman’s diagnosis of the man?
17. What might be the cause of the man’s illness?
18. In order to recover soon, which of the following should the man avoid eating or drinking?
19. According to the woman, when should the man take medication?
20. What does the woman think about the man’s condition?