Back in the 1860s, a British scientist named Henry Walter Bates noticed something interesting in the animal world: a kind of butterfly, Common Mormon, can change the pattern on its wings so that it looks like another butterfly species, the Common Rose, which is poisonous for birds to eat.

    Bates argued that animals develop this ability to protect themselves from being eaten. This theory had been widely accepted by scientists. But one question remains: how do these animals manage to do that?

    After more than 150 years, scientists are finally able to answer that question-it is all down to a gene(基因) called “doublesex", according to a study published on March 6 in the journal Nature.

    In fact, scientists have long known that genes are responsible for this useful ability. But until the new study, scientists hadn't been able to find out which genes in particular were responsible.

    Scientists at the University of Chicago compared the genetic structures of the Common Mormons that changed their wing patterns with those of ones that did not. And all the results pointed to a single gene, “doublesex”.

    This was much to the scientists' surprise. They used to expect that something as complex as this would be controlled by many different genes. For example, one gene would control the color of the upper part of the wing, one would do so for the lower part.

    However, the “doublesex” gene doesn't quite do everything by itself. Instead, it acts like a switch-it “tells” other genes to change the wing patterns. Isn't that clever?

    Scientists believe that this special ability of the “doublesex” gene on Common Mormon was developed throughout the long history of evolution. “The harmless species gains an advantage by resembling something predators(捕食者) avoid,” Sean Carroll, a scientist told Nature. “it was obvious evidence for natural selection.”

    A long time ago, soldiers fought wars on foot. Then they began to ride horses to battle. Until the invention of the stirrups (马蹬), though, men could not fight well with swords or spears while on horseback.

    Without stirrups, soldiers had no place to put their feet. They could not stand up to use their swords without falling off their horses. They could throw spears only with the force of their arms.

    Using stirrups, a soldier could stand up in his saddle (鞍). He could put a spear under the top part of his arm and charge with the force of his horse. He could use force when fighting with a sword. And he could win most fights against soldiers who did not use stirrups.

    The first stirrups were made in India. Because the weather was warm, people did not wear shoes. The Indian stirrup was made of rope. It fit around the big toes. Later, the Chinese made a foot stirrup of wood. Because the Chinese lived in a colder country, the stirrup had to fit around shoes. Still later, around A. D. 700, soldiers in Asia used strong iron foot stirrups.

    Many of the world's most successful people were once successful failures. Here are the stories of a few of them.

    Abraham Lincoln (1809-1865)

    Abraham Lincoln was one of America's greatest leaders, taking the country through the Civil War (from 1860 to 1865). However, his life was never easy. He started numerous businesses that failed, he went bankrupt twice, and was defeated in 26 campaigns for public office. He later said, “My great concern is not whether you have failed, but whether you are content and satisfied with your failure.”

    Vincent Van Gogh (1853-1890)

    Van Gogh is one of the most famous and influential painters in the history of Western Art. He's famous for paintings such as The Starry Night, The potato Eaters and Sunflowers. However, during his lifetime, Van Gogh sold only one painting for a very small amount of money. Despite this, he carried on painting, sometimes even going without food so he could complete his collection of over 800 known works.

Albert Einstein (1879-1955)

    Albert Einstein won the Noble Prize in Physics in 1921. However, he wasn't always considered a genius. He didn't speak until he was four, and couldn't read until he was seven. His teachers and parents thought he was slow, so he was driven from school and couldn't get into the Zurich Polytechnic School. He later famously said, “Success is failure in progress.”

    Stephen King (1947-2018)

    Stephen King is one of the best-selling authors of all time, but his first book, Carrie, was rejected by about 30 publishers. Finally, Stephen threw it into the bin, but his wife fished it out and encouraged him to resubmit it, which he did and succeeded this time!

    The flowers are blooming and the birds are singing as Melinda sits in the rose garden of the nursing home. She is recalling old times as she waits for her family's arrival. The nursing home has been Melinda's new settlement ever since Thomas passed away a week ago. Thomas had fought a long and hard battle against lung cancer for three years. Unfortunately, he has broken the promise that he and Melinda had made: to be with each other for every birthday. Melinda knew this was unrealistic (不现实的) but agreed to the promise for Thomas's sake.

    "Thomas, you are completely a dreamerl" Melinda shouted to Thomas as he dragged on about living on an island with his beautiful wife. That's what she loved about him most-he had a vivid imagination. They got married at age eighteen and began having children right away. Mary came within the year, followed by Thomas Benjamin II, Lilly-Ann, and Joseph "Little Joey" George. The family lived an exultant life filled with laughter and love.

    "Mom!" Lilly shouted, but it really sounded like a howl. Melinda had lost herself in thinking about the life she had shared with her late husband. Lilly pushed her down the long dark halls of the nursing home until they arrived at the recreational room.

    When the doors opened, Melinda put her hand over her mouth and was completely speechless. The room was crowded with the people nearest and dearest to her and the warmth and love was felt instantly. The night went on; stories and cocktails were shared and everything was perfect.

    However, when Melinda caught a moment to herself she looked around at her family. With a smile on her face, she raised her Manhattan and called out for a toast. "This one is for you, Thomas, though you are not here."

Four Best Shows for Toddlers (学步的孩童)

Peppa Pig

If you're looking for a British TV show for toddlers, look no further than Peppa Pig. This charming series will have your little one love Peppa and her family as they start their adventures through life in a colorful world.

Each episode of Peppa Pig is like a colorful storybook, combining five parts into 25 minutes of pure joy. Not only is it entertaining, but it also teaches essential social skills, such as kindness, loyalty, and thoughtfulness, making it an ideal choice for young kids and preschoolers.

Sesame Street

If you have fond memories of watching Sesame Street back in the day, why not pass on some of that magic to your little one? The show now is in its 54th season, which is the longest running program of the four shows, and the whole group is still bringing the fun. Not only is the 30-minute program still a crash course in all things smart, with numbers and words on the menu, but there's also wonderful music.

Daniel Tiger's Neighborhood

Step into the interesting world of Daniel Tiger, the lovable star of this show that's a popular offshoot (分支) of the timeless Mr. Roger's Neighborhood. With a runtime of 30 minutes, this show offers plenty of learning opportunities through engaging stories and catchy musical numbers.

Curious George

If you have fond memories of your parents reading Curious George books, you're in for a treat! The beloved stories were transformed into a charming lively series on PBS in 2006, ideal for toddlers. Each episode clocks in at a solid 30 minutes, and it's all about encouraging kids to be as curious and eager to explore as George himself.