It might be something that you miss unless it's pointed out to you. Next time you go to a public bathroom, take a look before you sit down on the toilet seat. You won't see a circle shape, but something designed not connected in the front part: a U.

    This is an open-front toilet seat, and thanks to the American Standard National Plumbing (水管装置) Technology, it's the go-to for most public restrooms. This technology was created in 1955 and further developed by the Uniform Plumbing Technology in 1973, according to Mental Floss.

    As to the plumbing rules which fit water seats, the first two requirements are as follows:

    Toilet seats shall be of smooth, non-absorbed material.

    All Toilet seats, except those within apartment units, shall be either of the open front type or have an automatic seat cover.

    This part of the rules also clears up why you won't meet fur toilet seats in truck stop bathrooms. The reason for both of these rules comes down to health. With an open front, there's less surface area that can make incidental touch with your private regions. But what about the toilet seat covers you can use? Unfortunately, those don't offer as much protection against bacteria as you think they do.

    They were also designed with women in mind, according to Lynne Simick, the senior vice president of technology development at IAPMO. The open front of the seat is fairly good for women.

Now that you know why the public toilet seat is shaped the way it is, learn which one is the cleanest you can use.

    It is interesting to see that the force of only 6 or 7 people pushing in the same direction can cause up to 1,000 pounds of force-enough to break brick walls. During a deadly stampede(逃奔), people can even die standing up. People die when pressure is put to their bodies in a front to back direction, causing them not to be able to breathe.

    If you are in a crowd, the first and most important thing is to make yourself familiar with your surroundings and find different exits. No matter where you are, make sure you always know how to get out.

    Make yourself aware of the type of the ground you are standing on, and know that in a crowd of moving people wet ground can cause you to fall.

    When in danger, a few seconds can make a difference, giving you the possibility of making use of your escaping route. Always stay closer to the escape route. If you find yourself in the middle of a moving crowd, do not fight against the pressure, do not stand still or sit down, because you can easily get trampled（踩踏）. Instead, move in the same direction of the crowd; make use of any space that may open up to move sideways to the crowd movement where the flow is weaker.

    Keep your hands up by your chest, like a boxer-it gives you movement and protects your chest. If you fall, get up quickly. If you can't get up because you are injured, get someone to pull you up. If you have kids, lift them up.

    If you fall and cannot get up, keep moving in the same direction of the crowd, or if that is not possible, then cover your head with your arms; do not lie on your stomach or back.

    In our everyday lives we meet situations in which we take many things for granted（不去重视）.We only treasure things when they are gone.This is a sad truth of human nature.One day,I found myself as a witness to a similar situation.

    One evening,I left work and boarded the train.After entering,I noticed something unusual.The center of the car had a few empty seats while both ends were crowded with people standing.I didn't pay much attention and sat down on one of the empty seats.I sensed a funny smell.It wasn't long before I noticed a homeless person sleeping on three seats in front of me.He was bleeding from his nose.Why wasn't anyone helping him?

    His clothes were torn and he was giving off a strange smell.Along with the smell,his eyes were dull,watery and red.Occasionally he scratched himself and people looked at him as if he had committed a crime.As the train stopped at stations and more people came in they covered their noses and faced away from him.All the seats around him were empty.

    Suddenly,he began to swear at the people around him.A plain clothes policeman who looked like a construction worker took out his certificate and showed it to the homeless man.The officer,not wanting to touch the homeless man, told him his rights and directed him to exit the train.As the officer walked the man out of the train,the homeless man turned around and said "MY HOME!" and started crying.

    A man doesn't value things until they are gone.If he didn't have a home,at least he had freedom.Now he has neither.No one wants to help someone who won't help himself.

    After a homeless man offered a college student in England all the money he had so she'd be able to get home safely, the woman is paying it forward—in a massive way.

    The story began in early December. It was about 3 a.m. and Harrison-Bentzen was panic. “I came out after a student night out and realized I didn't have any battery on my phone. I'd lost my friends,” the 22-year-old told BBC Radio 5. She'd also lost her bank card, she discovered, and she had no money.

    Just then, a homeless man, known only as Robbie, approached the young woman and asked her if she needed help. He reached into his pocket and pulled out all the money he had—loose change amounting to about $4.60. He insisted that Harrison-Bentzen take it to pay for a taxi so she'd get home safely.

    Harrison-Bentzen, a student at the University of Central Lancashire in Preston, England, says she refused to take Robbie's money and found another way to get home. But following her encounter（偶然相遇）with the generous man, she says she couldn't get him out of her mind.

    For the next few days, the student searched for Robbie, driving around the streets with her mom and using social media in an attempt to locate the man. In that time, Harrison-Bentzen says she learned more about Robbie and discovered that he actually had a reputation for helping strangers.

    Finally, after four days of driving around Preston, Harrison-Bentzen found Robbie. She was determined to do something to help change Robbie's life.

    So, earlier this month, the student launched a fundraising campaign in Robbie's name. She explained that she would be spending 24 hours on the streets, so as to “understand the difficulties” that the homeless face on a daily basis.

    Harrison-Bentzen says she had initially（最初）hoped to raise about $780 with her campaign. Her expectations, however, were quickly blown out of the water. As of Thursday morning, 4,800 people have donated almost $50,000.

    Washington, D.C. Bicycle Tours

    Cherry Blossom Bike Tour in Washington, D.C.

    Duration: 3 hours

    This small group bike tour is a fantastic way to see a world-famous cherry trees with beautiful flowers of Washington, D.C. Your guide will provide a history lesson about the trees and the famous monuments where they blossom. Reserve your spot before availability—and the cherry blossoms—disappear!

    Washington Capital Monuments Bicycle Tour

    Duration: 3 hours (4 miles)

    Join a guided bike tour and view some of the most popular monuments in Washington, D.C. Explore the monuments and memorials on the National Mall as your guide shares unique facts and history at each stop. Guided tour includes bike, helmet, cookies and bottled water.

    Capital City Bike Tour In Washington, D.C.

    Duration: 3 hours

    Morning or afternoon, this bike tour is the perfect tour for D. C. newcomers and locals looking to experience Washington, D.C. in a healthy way with minimum effort. Knowledgeable guides will entertain you with the most interesting stories about Presidents, Congress, memorials, and parks. Comfortable bikes and a smooth tour route(路线) make cycling between the sites fun and relaxing.

    Washington Capital Sites at Night Bicycle Tour

    Duration: 3 hours(7miles)

    Join a small group bike tour for an evening of exploration in the heart of Washington, D.C. Get up close to the monuments and memorials as you bike the sites of Capitol Hill and the National Mall. Frequent stops are made for photo taking as your guide offers unique facts and history. Tour includes bike, helmet, and bottled water. All riders are equipped with reflective vests and safety lights.

    They hide in trees, hang from helicopters, even follow people down on motorcycles—all so that they can snap a shot of a celebrity. They are paparazzi—photographers who make a living by taking pictures of the rich and famous.

    This September, California, a state with plenty of celebrities, passed a law aimed at taking action against paparazzi. The law forbids photographers from entering private property to take pictures, from using high-tech devices to take pictures of people on private property, and from "persistently following in order to take a picture." Violators can be fined or spend time in prison. The United State Congress is considering passing a similar law.

    Supporters of the California law say it will protect the privacy of celebrities, whom paparazzi have been bothering for years. Opponents (反对者) say the law restricts photojournalists from doing their job.

    Most celebrities seem to like having their pictures taken when they are in public at award shows or other events. After all, it's free publicity. But when they're not in public, they say, photographers should leave them alone. Yet paparazzi have been known to secretly look in windows and worse. Actor Michael J. Fox said that paparazzi have even "tried to pretend to be medical personnel at the hospital where my wife was giving birth to our son."

    Celebrities have as much right to their privacy as anyone else, supporters of the law state. Supporters further argue that the California law is a fair way to keep the press at bay, because the law still allows photographers to do their job. It only punishes them, supporters say, when they violate celebrities' privacy.

    Opponents of the law say it violates the First Amendment to the United States Constitution (美国宪法第一修正案), which guarantees that no laws will be made to limit "the freedom of speech, or of the press." Although some people might not consider paparazzi a part of the legal press, the California law does not single out paparazzi. It applies to photographers working for any publication.

    Opponents of the law are also concerned about its wording. "Does 'persistently' mean following someone for six minutes, six seconds, or six days?" asked lawyer Douglas Mirell. The wording of the law is too vague, critics complain, and could be used to punish almost any news photographer.

    The United States needs a free press to keep the public informed about important news, paparazzi law opponents say. Limiting the press in any way, they argue, limits the freedom of all.