One of the first great intellectual achievements of a young child is learning how to talk, closely followed by learning how to count. From earliest childhood we are so associated with our system of numeration(计数)that it is hard to consider the problems faced by early humans who had not yet developed this ability. Rather than being an ability that comes naturally to a person, it is one of the great achievements of the human race.

It will never be known how and when this numeration ability developed, but it is certain that numeration was well developed by the time humans had formed even semi-permanent settlements. When early humans began to settle, grow plants and herd animals, the need for a complex number system became important.

Evidence of early stages of numeration can be readily found. The indigenous (土著的) peoples of Tasmania were only able to count one, two, many. But in real situations the number and words are often accompanied by gestures to help smooth any confusion. For example, when using the one, two, many type of system, the word many would mean. Look at my hands and how many fingers I am showing you. This approach is limited in the range of numbers that it can express, but generally enough.

The lack of ability of some cultures to deal with large numbers is not really surprising. The average person in the seventh century in Europe was not as familiar with numbers as we are today. In fact, to qualify as a witness in a court of law, a man had to be able to count to nine！

Counting is not directly related to the formation of a number concept because it is possible to count by matching the items being counted against a group of pebbles or fingers. Such aids, while different, are still used even by the most educated in today s society due to their convenience.

Some birds are inside decorators, placing big, showy feathers in their nests. But rather than beautifying their homes, these birds may be trying to scare nest-stealing neighbors.

Birds sometimes weave feathers into their nests to provide insulation (隔绝). But behavioral ecologists Karen Wiebe and Tore Slagsvold also saw birds placing large feathers on the surfaces of nests. Those feathers wouldn’t help with warmth. The researchers wondered whether the birds might be using the decorations to send a message.

For birds that nest in holes, competition for nests can be really fierce. Birds scream and fight, sometimes killing an opponent. But these holes can also hide danger. Eagles or other predators may be hiding inside. If a nest contains feathers or other remains, it might be evidence that a predator had been there. Those holes might not be desirable.

During spring, when nest competition is the fiercest, the researchers set up pairs of nesting boxes. One box contained white feathers. The other either contained no feathers or black feathers. Inside the boxes, black feathers were more difficult to see than white ones. Using video cameras, the researchers spied on how tree swallows, blue tits, and pied flycatchers reacted to the boxes. They watched how long birds waited to explore a nest box. When birds took longer to enter, that suggested the birds were scared.

Birds of all three species hesitated to enter boxes with white feathers. But when feathers were in front of a nest, birds jumped right up and grabbed them. That suggested that birds weren’t afraid of the feathers themselves.

“It was really interesting to discover that birds were using a trick to help them keep their nests,” Wiebe says. “When a bird leaves its nest to search for food, it opens the door for a nest stealer. But if it can buy a little time by scaring away intruders (不速之客) with these feathers, then it has a better chance of coming back in time to defend its nest site.”

“Do you want fries with that?” For the average American, who eats 29 pounds of fries each year, the response to this irresistible question is a resounding yes. McDonald’s alone sells 9million pounds of fries globally every day. To keep up, its U. S. supplier uses an extremely large fry-cutting machine that shoots potatoes through at 60 to 70 miles per hour, 24 hours a day.

It’s hotly debated whether fries first came from France or Belgium, but it was American soldiers during World War I(1914-1918)who named them “French.” The soldiers became smitten with the potatoes in southern Belgium—where villagers fried sliced potatoes instead of fish when the River Meuse froze over—but called them French since that was the most spoken language. The name stuck.

Many chefs agree an ideal fry is achieved with a double-dunk (浸泡) in hot oil: The first bath forms the fries’ initial outer layer, and the second crisps that layer to a beautiful golden brown. Still, famous fry-makers differ in how they deep-fry: Five Guys uses peanut oil, while McD’s adds “natural beef flavor” to its vegetable oil. Shake Shack now turns to a nostalgic frozen crinkle-cut (波纹薯条) after switching to a freshly made straight-cut version and making their fans angry. As CEO Randy Garutti said, “When we sent out the Instagram of crinkle-cuts coming back, it’s to this day the most-liked thing we’ve ever done.”

How one dips a fry alters the experience. Since the rise of fast food in the 1940s, the dunk er of choice has been classic ketchup. But in their likely birthplace of Belgium, fries are served with mayonnaise. In Utah, the two dips are combined into a zippy pink “fry sauce.” Or perhaps you prefer to dunk them in a chocolate milkshake, making the better question: “What do you want with your fries?”