We all know that cycling is a greatly exercise. A doctor tells me people who lives the longest are dancers and cyclists. Maybe it is because the combination of fresh air, smooth movement and exercise. Whether you ride a bicycle, you don’t use petrol. So they are not producing carbon dioxide and not cause air pollution. Just see how cars have been taken over our cities. They often run at high speeds, what may put our lives in danger. And there were traffic jams, too. Our cities will be better places if we replace cars with bicycle.

5 . There is a popular saying in the English language: “Sticks and stones may break my bones, but words will never hurt me.” Well, that is not true. Unkind words, name-calling or even the so-called “the silent treatment” can hurt children as much as being physically hit, sometimes even more so. A recent study of middle school children showed that verbal (言语的) abuse by other children can harm, the development in the brain. The study was a project of researchers at Harvard Medical School in Massachusetts. Researcher Martin Teicher and his team studied young adults, aged 18 to 25. These young men and women had not ever been treated in a cruel or violent way by their parents. The researchers asked the young people to rate their childhood exposure to verbal abuse from both parents and other children. Then the researchers performed imaging tests on the brains of the subjects.

The images showed that the people who reported suffering verbal abuse from peers in middle school had underdeveloped connections between the left and right side of the brain. The two sides of the brain are connected by a large bundle of connecting fibers called the corpus callosum. This was the area that was underdeveloped.

The middle school years are a time when these brain connections are developing. So, unkind, hurtful comments from children or adults during this period have the greatest effect. The researchers tested the mental and emotional condition of all the young people in the study. The tests showed that this same group of people had higher levels of fear, depression, anger and drug abuse than others in the study.

The researchers published their findings online on the American Journal of Psychiatry's website.

Parents cannot control what other people say to their children, but they can prepare their children.

6 . 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?

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.

If it weren’t for Rachel Carson, the environmental movement might not exist today. Her popular 1962 book Silent Spring raised awareness(意识) of the dangers of pollution and the harmful effects of chemicals on humans and on the world’s lakes and oceans.

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 (最高法院). O’Connor gave the deciding vote in many important cases during her 24 years on the top court.

On December 1,1955, in Montgomery, Alabama, Rasa 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 (抵制). 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.

7 . Today’s world is not an easy adjustment for young adults. A key skill set for success is persistence (毅力), a characteristic that researchers say is heavily influenced by fathers. Researchers from Brigham Young University discovered that fathers are in a unique position to help their adolescent children learn persistence.

BYU professors Laura Padilla-Walker and Randal Day arrived at these findings after following 325 American families over several years. And over time, the persistence gained through fathers led to higher achievement in school.

“There are relatively few studies that stress the unique role of fathers,” Padilla-Walker said. “This research also helps to prove that characteristics such as persistence — which can be taught — are key to a child’s life success.”

Researchers determined that dads need to practice an “authoritative” parenting style. Authoritative parenting is not authoritarian: rigid, demanding or controlling. Rather, an authoritative parenting style includes some of the following characteristics: children feel warmth and love from their father; responsibility and the reasons behind rules are stressed; children are given an appropriate level of autonomy (自主权).

In the study, about 52 percent of the dads exhibited above-average levels of authoritative parenting. A key finding is that over time, children raised by an authoritative father were significantly more likely to develop persistence, which leads to better outcomes in school.

This particular study examined 11 to 14-year-olds living in two-parent homes. Yet the researchers suggest that single parents still may play a role in teaching the benefits of persistence, which is an avenue of future research.

9 . Around the world, 62 million girls are not in school. The White House's Let Girls Learn effort aims to change that.

At 13, Hawa Abdulai Yorke left her family's home, in Ghana, Africa, to live with an aunt who promised to send her to school. Instead, the aunt put Yorke to work as her maid. Determined to go to school, Yorke returned home and began selling water in a nearby city to raise money for her education. She did that for three years. What hurt most was that her father had the money to pay the school fees. But he chose to spend the money on a motorcycle.

Yorke's story is familiar to girls growing up in Ghana. There, a girl's place is in the home. Educating girls is considered a waste of money.

"It happens more than it should, where parents have money to send their girls to school but choose not to," says Ryan Roach, a Peace Corps volunteer in Ghana, where nearly 55% of girls are not enrolled in secondary school. "Cultural beliefs say education is not a wise investment".

The White House's Let Girls Learn is working to change this view of girls' education, in Ghana and in countries worldwide. First Lady Michelle Obama says parents have to be persuaded that girls' education is a better investment than marriage or household labor. A World Bank study backs that up. It shows that for every year of secondary-school education, a girl's earning power increases by 18%.

Today, Let Girls Learn works in 13 countries, and there are plans to expand the program. Recently, Let Girls Learn hosted a 24-hour event at which girls in different parts of Ghana joined Peace Corps volunteers, tech experts, and university students to brainstorm creative solutions for the barriers to girls' education. Yorke's team came up with an idea for an app that sends a recorded message to parents' phones from a Ghanian celebrity about the benefits of girls attending school.

Yorke, now 22, is about to finish high school. Thanks to Let Girls Learn, she plans to attend college and study computer science. She says working alongside women college students at the Let Girls Learn event strengthened her determination. "I'm focused on my books," says Yorke. "I know if I study hard, I, too, can go to the university and live a happy life."

10 . It’s time to reconsider food. Around the globe, food problems threaten wildlife, wild places and the planet itself. Today, 7.3 billion people consume 1.6 times _______ the earth’s natural resources can supply. By 2050, the world’s population _______(reach) 9 billion and the demand for food will double.

So how do we produce more food for more people without _______(expand) the land and water already in use? We can’t double the amount of food. _______(fortunate), we don’t have to — we just have to double the amount of food available now instead. _______ short, we must freeze the footprint of food.

In the near-term, food production is enough to provide for all, but it doesn’t reach everyone who needs it. About 1.3 billion tons of food _______(waste) each year — four times the amount _______(need) to feed the more than 800+ million people who are _______(hunger).

By improving efficiency and productivity while reducing waste and shifting consumption _______(pattern), we can produce enough food for everyone by 2050 on roughly ________ same amount of land we use now.