Questions 21 to 30 are based on the following passage.
【真题来源：2015年12月大学英语四级真题（第二套）Part Ⅲ，Section B，第46-55题】

How to Eat Well

A) Why do so many Americans eat tons of processed food, the stuff that is correctly called junk(垃圾) and should really carry warning labels?

B) It's not because fresh ingredients are hard to come by Supermarkets offer more variety than ever, and there are over four times as many famers' markets in the U.S. as there were 20 years ago. Nor is it for lack of available information. There are plenty of recipes(食谱), how-to videos and cooking classes available to anyone who has a computer, smartphone or television. If anything the information is overwhelming.

C) And yet we aren't cooking. If you eat three meals a day and behave like most Americans, you probably get at least a third of your daily calories(卡路里) outsides the home. Nearly two-thirds of us grab fast food once a week, and we get almost 25% of our daily calories from snacks. So we're eating out or taking in, and we don't sit down—or we do, but hurry.

D) Shouldn't preparing—and consuming—food be a source of comfort, pride, health, well-being, relaxation, sociability? Something that connects us to other humans? Why should we want to outsource(外包) this basic task, especially when outsourcing it is so harmful?

E) When I talk about cooking, I'm not talking about creating elaborate dinner parties or three-day science projects. I'm talking about simple, easy, everyday meals. My mission is to encourage green hands and those lacking time or money to feed themselves. That means we need modest, realistic expectation, and we need to teach people to cook food that's good enough to share with family and friends.

F) Perhaps a return to real cooking needn't be far off. A recent Harris poll revealed that 79% of Americans say they enjoy cooking and 30% “love it”; 14% admit to not enjoying kitchen work and just 7% won't go near the stove at all. But this doesn't necessarily translate to real cooking and the result of this survey shouldn't surprise anyone; 52% of those 65 or older cook at home five or more times per week; only a third of young people do.

G) Back in the 1950s most of us grew up in households where Mom cooked virtually every night. The intention to put a home-cooked meal on the table was pretty much universal. Most people couldn't afford to do otherwise.

H) Although frozen dinners were invented in the 40s, their popularity didn't boom until televisions became popular a decade or so later. Since then packaged, pre-prepared meals have been what's for dinner. The microwave and fast-food chains were the biggest catalysts(催化剂),but the big food companies—which want to sell anything except the raw ingredients that go into cooking—made the home cook an endangered species.

I) Still, I find it strange that only a third of young people report preparing meals at home regularly. Isn't this the same crowd that rails against processed junk and champions craft cooking? And isn't this the generation who say they're concerned about their health and the wee-being of the planet? If these are truly the values of many young people, then tier behavior doesn't match their beliefs.

J) There have been half-hearted but well-publicized efforts by some food campaigns to reduce calories in their processed foods, but the Standard American Diet is still the polar opposite of the healthy, mostly plant-based diet that just about every expert says we should be eating. Considering that the governments standards are not nearly ambitious enough, the picture is clear: by nor cooking at home, we're not eating the right things, and the consequences are hard to overstate.

K) To help quantify(量化) the costs of a poor diet, I recently tried to estimate this impact in terms of a most famous food, the burger(汉堡包). I concluded that the profit from burgers is more than offset(抵消) by the damage they cause in health problems and environmental harm.

L) Cooking real food is the best defense —not to mention that any meal you're likely to eat at home contains about 200 fewer calories than one you would cat in a restaurant.

M) To those Americans for whom money is a concern, my advice is simple; Buy what you can afford, and cook it yourself. The common prescription is to primarily shop the grocery store, since that's where fresh produce, meat and seafood, and dairy are. And to save money and still eat well you don't need local organic ingredients; all you need is real food. I'm not saying local food isn't better, it is. But there is plenty of decent food in the grocery stores.

N) The other sections you should get to know are the frozen foods and the canned goods. Frozen produce is still produce; canned tomatoes are still tomatoes. Just make sure you're getting real food without tons of added salt or sugar. Ask yourself, Would Grandma consider this food? Does it look like something that might occur in nature? It's pretty much common sense: you want to buy food, not unidentifiable foodlike objects.

O) You don't have to hit the grocery store daily, nor do you need an abundance of skill. Since fewer than half of Americans say they cook at an intermediate level and only 20% describe their cooking skills as advanced, the crisis is one of confidence. And the only remedy for that is practice. There's nothing mysterious about cooking the evening meal. You just have to do a little thinking ahead and redefine what qualifies as dinner. Like any skill, cooking gets easier as you do it more; every time you cook, you advance your level of skills. Someday you won't even need recipes. My advice is that you not pay attention to the number of steps and ingredients, because they can be deceiving.

P) Time, I realize, is the biggest obstacle to cooking for most people. You must adjust you priorities to find time to cook. For instance, you can move a TV to the kitchen and watch your favorite shows while you're standing at the sink. No one is asking you to give up activities you like, but if you're watching food shows on TV, try cooking instead.

Cooking benefits people in many ways and enables them to connect with one another.

Abundant information about cooking is available either online or on TV.

Young people do less cooking at home than the elderly these days.

Cooking skills can be improved with practice.

In the mid-20th century, most families ate dinner at home instead of eating out.

Even those short of time or money should be encouraged to cook for themselves and their family.

Eating food not cooked by ourselves can cause serious consequences.

To eat well and still save money, people should buy fresh food and cook it themselves.

We get a fairly large portion of calories from fast food and snacks.

The popularity of TV led to the popularity of frozen food.