In its early history, Chicago had floods frequently, especially in the spring, making the streets so muddy that people, horses, and carts got stuck. An old joke that was popular at the time went something like this: A man is stuck up to his waist in a muddy Chicago street. Asked if he needs help, he replies,“No, thanks. I've got a good horse under me.”

    The city planners decided to build an underground drainage(排水) system, but there simply wasn't enough difference between the height of the ground level and the water level. The only two options were to lower the Chicago River or raise the city.

    An engineer named Ellis Chesbrough convinced the city that it had no choice but to build the pipes above ground and then cover them with dirt. This raised the level of the city's streets by as much as 12 feet.

    This of course created a new problem: dirt practically buried the first floors of every building in Chicago. Building owners were faced with a choice: either change the first floors of their buildings into basements, and the second stories into main floors, or hoist the entire bulidings to meet the new street level. Small wood-frame buildings could be lifted fairly easily. But what about large, heavy structures like the Tremont Hotel, which was a six-story brick building?

    That's where George Pullman came in. He had developed some house-moving skills successfully. To lift a big structure like Tremont Hotel, Pullman would place thousands of jackscrews(螺旋千斤顶) beneath the building's foundation. One man was assigned to operate each section of roughly 10 jackscrews. At Pullman's signal each man turned his jackscrew the same amount at the same time, thereby raising the building slowly and evenly. Astonishingly, the Tremont Hotel stayed open during the entire operation, and many of its guests didn't even notice anything was happening.

    Some people like to say that every problem has a solution. But in Chicago's early history, every engineering solution seemed to create a new problem. Now that Chicago's waste water was draining efficiently into the Chicago River, the city's next step was to clean the polluted river.

    Reducing plastic waste isn't easy because the cheap material is found in almost every household item. Now, a delicious and nutritious solution has come up to help reduce our dependence on this environmental hazard.

    David Christian, the co-founder of Evoware, says the idea of creating the biodegradable (生物降解的) products came from concern at the country's high pollution rate. Indonesia is home to four of the world's worst polluted rivers. Since single-use packaging is a large contributor to the problem, Evoware decided to deal with that first.

    After investigating various materials, the company settled on seaweed. Unlike com, commonly used for biodegradable containers, seaweed does not require resources like water or large amounts of space. Since Indonesian farmers already harvest more seaweed than they can sell, it's easy for the company to find the material.

    Though they will not reveal their production process, Evoware says the seaweed packaging contains no chemicals and is safe to consume. The company has also invented single-use cups, which can break down 30 days after they're thrown away.

    While replacing plastic with the seaweed products may seem appealing to most of us, it is a hard-sell in Indonesia. According to Christian, “The awareness to reduce single-use plastic is still very low. This makes our bioplastic unnecessary.” Also a factor is the cost, which is higher than using plastic. Hopefully, Evoware will succeed in convincing Indonesians and people worldwide that switching to their products will be helpful to protecting our beautiful planet.

    When we do something, we all have our own plans. Some people are born planners. I can't claim (宣称) to be one of that kind of people. Most of the time, I try to at least expect what might go wrong. I have taken to making lists and, although I'm not yet achieving perfection, I usually manage to achieve goals. But there are times when even the best plans do not succeed. All that is left then is to smile and to make or do something using whatever is found.

Hanukkah (光明节) came early this year, perhaps too soon after Thanksgiving to allow us to prepare well. During the first night of Hanukkah, the Hanukkah candles were nowhere to be found in the entire Dallas area where we lived. Birthday candles wouldn't work! The tall long thin candle fell in small drops. "What would our ancestors do?" I thought. "What shall I do now? That's where ingenuity comes from. Don't be nervous and worried. Never let missing candles spoil a family celebration." Later what we did find was a bag of tea lights. The long, silver bread tray became the base for our tea lights. The younger ones were wide-eyed and happy as Grandpa lit the first tea light and all recited the blessing. We sat at the dining table, happy to be together and the food was plentiful.

    No matter how imperfect it is, the fact that families gather to share a special event, an event that has held meaning for so many generations of families, is the meaning itself and forms the important part of the observance (仪式). What we need to remember, and to carry with us, is the knowledge that togetherness is much better than all other concerns.

    Physics is a different world now. Will there ever be another Einstein?

    Scientists say a new Einstein will appear, but it may take a long time. After all, more than 200 years separated Einstein from his nearest rival (对手) , Isaac Newton. Many physicists say the next Einstein hasn't been born yet, or is only a baby now. That's because the searching for a unified(统一的) theory that would explain all the forces of nature has pushed current mathematics to its limits. New math must be created before the problem can be solved.

    But researchers say there are many other factors working against another Einstein appearing anytime soon. For one thing, physics is quite a different field today. In Einstein's day, there were a few thousand physicists worldwide, and fewer theoreticians. Education is different, too. One extremely important aspect of Einstein's training that failed to be considered is the philosophy he read as a teenager. It taught him how to think theoretically about space and time.

    And he was a skilled musician. The interplay between music and math is well known. Einstein would fiercely play his violin as a way to think through a knotty physics problem.

    Today, universities have produced millions of physicists. There aren't many jobs in science for them, so they go to Wall Street and Silicon Valley to apply their analytical skills to more practical and rewarding efforts.

    Besides, those who stay in science don't work alone. It's very difficult to imagine an independent person like Einstein ever tolerating this.

    We all long for friendship, but how to make a friend? "The best time to make a friend is before you need one." Joy Steven said. The following are some tips for you.

    People equal friends

    Friends usually begin with strangers. Getting in touch with other people is the first step to make a friend. Friends can't be made in empty air. Best friends take time to make.

    Friends understand friends

    Friends understand each other when talking. Many unpleasant personal quarrels can be avoided if you will take the time to understand others' feelings and points of view.

    Friends touch friends

    Touching is a warm from of communication between friends. When you see best friends communicating, you will notice them stand close together, touch each other comfortably and listen to each other. Sometimes a friendly touch is more powerful than words.

    Friends praise friends

    Praise is a powerful tool to make a friend. Honest praise can affect (影响) your friends' lives. So try to praise your friends, including your general ones.

    Friends can loyal (忠诚的) and trustworthy

    Trust and loyalty go hand in hand for friends. Friends can share secrets with you, because good friends never break confidence (信心) and are loyal forever.

    About three decades ago, China was known as the "Bicycle Kingdom".But the two­wheeled transport's popularity began to fade, with many bikes soon replaced by their fuel­powered competitors.

    But recent months have seen a renaissance of the bike across China, with an increasing number of people choosing cycling instead of driving to schools, to workplaces or to do sightseeing. The introduction of bike­sharing schemes, first developed by new companies like Ofo and Mobike, has brought the trend to a new level. According to data from iResearch Consulting Group, the first week of this year saw 5.85 million active users of Mobike while Ofo had 1.4 million active users.

    People can unlock the shared bikes by simply using their smartphones. The bikes are equipped with GPS and can be left anywhere in public places for the next user. They're popular among many Chinese people as they provide an effective answer to the "last mile" problem, which refers to a person's final journey. "In places where the subway doesn't reach and where it's difficult to change from one kind of transport to another, it's so easy to get where you want to go with Mobike," Hu Hong, 29, said. She rides a bike to work.

    However, the schemes have also led to problems such as illegal parking, vandalism (故意破坏) and theft. "Bike­sharing is a greener method of transportation and provides a user­friendly experience," said Liu Xiaoming, Vice­Minister of Transport. "But it's a combination of online and offline business. Operators are usually strong in online services, but lack offline business experience."

    In fact, these problems are also shared by bike­sharing schemes abroad. Set up in 2007, Vélib is a large­scale public bike sharing system in Paris. By October, 2009, a large number of Vélib's initial bikes had to be replaced due to vandalism or theft. Bikes were found hanging from lampposts (街灯柱) or thrown into the Seine River.