You probably know who Marie Curie was, but you may not have heard of Rachel Carson. Of the outstanding ladies listed below，who do you think was the most important woman of the past 100 years?

Jane Addams (1860－1935)

    Anyone who has ever been helped by a social worker has Jane Addams to thank. Addams helped the poor and worked for peace. She encouraged a sense of community (社区) by creating shelters and promoting education and services for people in need. In 1931，Addams became the first American woman to win the Nobel Peace Prize.

Rachel Carson (1907－1964)

    If it weren't for Rachel Carson, the environmental movement might not exist today. Her popular 1962 book SilentSpring raised awareness of the danger of pollution and the harmful effects of chemicals on humans and on the world's lakes and oceans.

Sandra Day O'Connor (1930－present)

    When Sandra Day O'Connor finished third in her class at Stanford Law School, in 1952, she could not find work at a law firm because she was a woman. She became an Arizona state senator (参议员) and，in 1981, the first woman to join the U．S. Supreme Court. O'Connor gave the deciding vote in many important cases during her 24 years on the top court.

Rosa Parks (1913－2005)

    On December 1, 1955, in Montgomery, Alabama, Rosa Parks would not give up her seat on a bus to a white passenger. Her simple act landed Parks in prison. But it also set off the Montgomery bus boycott. It lasted for more than a year, and kicked off the civil ­ rights movement. “The only tired I was, was tired of giving in，”said Parks.

    More than a hundred years ago, two boys were fishing in a small river. They sat in a heavy-bottomed boat, each holding a long, bent pole in his hands and eagerly waiting for "a bite". When they wanted to move the boat from one place to another they had to push against a long pole into the bottom of the stream.

    "This is slow work, Robert," said the older of the boys. "Yes, Christopher, and it's hard work, too." answered Robert. "I think there's some better way of moving a boat."

    Christopher advised rowing it and Robert promised to make some paddles (桨). The next day Robert's aunt heard a great noise in her house. The two boys were there, busily working. "What are you making, Robert?" she asked. He told his plan. His aunt laughed and said, "Well done! I hope you'll succeed."

    After much work, they succeeded in making two paddle wheels. They were very rough, but strong and usable. They fixed each of these wheels to the end of an iron rod (长杆) which they passed through the boat from side to side. The rod was bent in the middle. When the work was finished, the old fishing boat looked rather strange, with a paddle wheel on each side. The boys lost no time in trying it. One of the boys could guide the boat while the other turned the paddle wheels.

    That night when Christopher went home, he told his father a wonderful story. "Robert Fulton planned the whole thing," he said, "and I helped him make the paddles and put them on the boat." When Robert Fulton became a man, he didn't forget his experiment with the old fishing boat. He kept on thinking and working, until at last he succeeded in making a boat with paddle wheels that could be run by steam. He's now honored as the inventor of the steamboat.

    Crossing your legs is an extremely common habit; most people don't even notice that they're doing it when they sit down. While you may find it comfortable to sit with one knee crossed over the other, it might be causing health problems that you are not aware of.

    A study published in Blood Pressure Monitoring stated that sitting with your legs crossed can increase your blood pressure. The reason for this is that the blood in your legs has to work against gravity to be pumped back to your heart and that crossing one leg over the other increases resistance(阻力), making it even harder for the blood to circulate. This causes your body to increase your blood pressure to push the blood back to the heart. You won't feel any immediate effects, but repeated, drawn-out increases in blood pressure can cause long-term health problems. So, planning to sit for a long period of time? Don't keep your legs crossed.

    Crossing your legs at the knee can also cause pressure on the major nerve in your leg that passes just below your knee and along the outside of your leg, explains Richard Graves, a medical expert. This pressure can cause numbness and temporary paralysis (麻痹) of some of the muscles in your foot and leg, preventing you from being able to raise your ankle—what we know as that “pins and needles” sensation. While the feeling of discomfort may only last a minute or two, repeatedly crossing your legs until they feel numb can cause permanent nerve damage.

    So next time you sit down, try to get yourself in the habit of sitting with both of your feet on the floor. Not only will it help your posture and stability, but it will also save your health in the long run.

    Grandma Pugh sized up the baby like a pig at the farmers' market. There was a pause and then she pronounced. "He's got nice long legs." She clapped her hands once in approval. But then she frowned and leaned forward. Everyone waited anxiously. The baby had opened his eyes and was staring up. "But those cross eyes won't do," she declared firmly, shaking her head in disappointment.

    That had been Freddie Pilcher's first meeting with Grandma Pugh. Since then, ten years had passed. Much to his grandmother's satisfaction, she'd been proven right about the boy's legs. He was a regular beanpole. Grandma Pugh had also been correct about his eyes. Freddie had been wearing glasses to correct his vision since he was two years old. His current pair was thick, and cheap-looking, but at least he could see.

    Freddie not only had poor eyesight, but he was also clumsy. He wasn't good at schoolwork either. But there was one thing that the boy was good at and it was all on account of the length of his legs. He could jump.

    Freddie was the best jumper in school. Not only could he leap the furthest but also the highest. At break times, he entertained the little ones by leaping over the school wall into Mrs. Hobson's garden and then rapidly jumping back. She had been up to see the head teacher several times because somebody had been crushing her vegetables.

    It was badgers (獾), Freddie suggested, when questioned by Miss Harpy—definitely badgers; no doubt about it. His dad had terrible problems with badgers. Only last week he had lost two rows of carrots. Freddie had woken one night and heard them tearing through the garden, a whole herd of them. They rooted up the lawn and dug up the vegetables. Terrible things, badgers. All the other children nodded their heads wisely. There was a moment's pause in Class Three as everyone thought about the dreadful damage that badgers could do.

In the movie, The Day After Tomorrow, many climate changes including an ice age are caused by global warming. Much of the science in the movie has been questioned by people. However, there may be some truth to the idea in the movie that global warming could cause an ice age.

The theory starts with an understanding of why Europe and Scandinavia are not colder already. After all, other places at the same latitude(纬度) are covered with ice. The ocean current called the Gulf Stream brings warm waters from the Caribbean to the UK and Europe. These waters warm the countries around their path. This is why the UK, Europe and Scandinavia have a warmer climate than Alaska. Global warming has nothing to do with this. Global warming is significant. It could slow the Gulf Stream, or even stop it. If this were to happen, the cold waters would stay in the area of Europe, the UK, Scandinavia and the Northeastern US. It could mean an ice age for those regions.

Some weaknesses in the Gulf Stream could happen for different reasons. These days, it could happen due to global warming, caused by human activities, such as the burning of fossil fuels.

If a new ice age happened, it would probably be caused by the melting of the polar ice. This will lead large quantities of cold and fresh water to come into the ocean, which would disrupt the Gulf Stream and cause the cooling of many areas that now have a mild climate.

Scientists have gathered a lot of data from the oceans and the land to try to determine whether an ice age could be caused by global warming. With all this information at hand, it appears that it is indeed possible that global warming could lead to an ice age.

"Consumers complain that the modern tomato has little flavor. It's like a water bomb," said Sanwen Huang, who works at the Agricultural Genomics Institute at Shenzhen at the Chinese Academy of Agricultural Sciences. "Tomato farmers care about yield, and the genetic variants related to yield are not related to tasty tomato flavors."

How can farmers ditch this unpleasant thing and recover the rich, sweet flavor of the tomato? To find out, Huang and colleagues investigated which genes are related to tomatoes' taste. The scientists created a 100-person group that sampled 160 tomatoes based on sensory qualities. Based on the group's feedback, the researchers identified dozens of chemical compounds(化合物) that could be related to the tomato's taste. Using a statistical model that determined the concentration of various chemicals in the tomatoes, the scientists identified 33 most important flavor compounds. The researchers then measured the content of them in each of the tomatoes, and identified about 250 genetic loci(基因座) that controlled tomato flavor. This finding revealed the genetic basis of tomato flavor.

But the researchers also wanted to determine why store-bought tomatoes don't taste good. It turns out that modern tomato varieties are selected according to qualities such as big size because buyers prefer large fruit, and firmness because it makes tomatoes easier to ship. Meanwhile, the quality of flavor has been ignored, said the researchers.

Volatiles(挥发性物质), in particular, are essential for good flavor. The removal of specific volatiles from tomatoes results in significant reduction in people's liking. Moreover, refrigeration can change a tomato's volatile compounds.

"But there is hope for a future filled with tasty, new varieties of store-bought tomatoes, as our results provide a road map for improvement of flavor. By working together, geneticists, biochemists, farmers and customers can provide better-flavored tomatoes for our society." Huang said.