We truly are what we eat—and what our ancestors ate. Food has changed who we are and how we developed for hundreds of thousands of years. From processing (加工) to preserving to cooking, what humans did and continue to do to food played a big role in shaping our evolution (进化).

“Processed food isn’t just a modern invention. It’s as old as human itself and may have helped create our species,” wrote Nicholas Temple, author of The Best Before: The Evolution and Future of Processed Food for the BBC.

Although processing is viewed negatively nowadays, it was important to our development as a species. Processing doesn’t necessarily mean adding chemicals. It also includes pounding or slicing or changing the food in anyway before eating. Compared to our ancestors, modern humans’ teeth, jaws and faces have gotten smaller because of making food easier to chew, especially from cooking.

Cooking food was one of the biggest changes in human history. Researchers believe it could have occurred between 1.8 million to 400,000 years ago. Without cooking, an average person would have to eat around five kilos of raw (未加工的) food to survive and will have to spend most of the day eating. Also, up to 50% of women who only eat raw foods develop a condition that signals that the body can’t support a pregnancy (怀孕) —a major problem for evolution, according to Science American. Processing food leads to a huge gain in leisure time. The less time people spent chewing, the more time they had to develop complex spoken language. Cooking food also breaks down its cells. So our stomachs need to work less to absorb the nutrients and save more energy, which could then be used to power a large brain.

Processed food actually shaped us as a species and made us human—the only species on earth who can cook.

【小题1】Why are modern humans’ teeth and jaws smaller?

A．Because they look much more beautiful.

B．Because they are suitable for cooked food.

C．Because humans become small in size.

D．Because humans have to adapt to modern life.

【小题2】What problem does eating raw food cause?

A．It takes people much time and energy.

B．It stops the evolution of human beings.

C．It causes people’s stomach to work less.

D．Its lows the development of written language.

【小题3】What can we learn from the passage?

A．Only modern people process food.

B．Some animals can cook food as humans.

C．Processed food is of great value to humans.

D．People began to process food in recent years.

【小题4】What is the main purpose of the passage?

A．To introduce various ways to process food in human history.

B．To uncover the details about the development of human food.

C．To present the findings of a study about food in human history.

D．To explain the importance of processed food to human beings.