A、Chemical element Na. B、Protein from fish. C、Vitamin C. D、High fat. A本题问的是根据男士的话，大部分快餐中都含有什么物质。对话中男士提到了自己已经不再吃汉堡这类食物，并补充说大部分的快餐

W: I can’t believe my eyes, Bill. Are you having a salad for lunch? No hamburger?
M: Get used to it, Susan. I’m off burgers for good.(l)Most fast food is loaded with Na—a kind of chemical substance. I’ve been reading about a new healthy snack food. It’s made from fish. Have you heard anything about it?
W: No, I haven’t. But I don’t like fish very much anyway. But why are you interested in lessening your salt intake?
M:(2)My doctor says I should cut back on Na-rich foods to lower my blood pressure. Actually, my blood pressure isn’t that high, but they say it increases with age.
W: I would have thought you were too young for that. Well, I’m glad you’re starting to pay more attention to your diet.
M: I’ve been eating lots of fruits and vegetables recently. I want to lower my risk of heart attack and stroke, too. Recently, my family are trying to eat more healthy food.
W: So am I.(3)That’s why I’ve been trying to lower my cholesterol(胆固醇)level. Just like you, I’m now trying to lose a few pounds, too.
M: In that case,(4)you should come to my health club with me. Can you tear yourself away from the TV tonight?
W: You’ve joined a health club? I would never have dreamed that you’d take something like this so seriously. (4)Why not? If you can break your unhealthy eating habits, I can surely break a sweat.
M: I can do 100 push-ups in a row. Don’t get jealous. You will do it someday.
1. Which substance can be found in most fast food according to the man?
2. Why does the man want to reduce salt in the food?
3. What problem does the woman have concerning health?
4. What is the woman going to do from now on?