The streams are about 12 to 15 feet wide and 300 feet or more long, scientists said. "What we're dealing with is wet soil, thin layers of wet soil, not standing water," said Aifred  McEwen of the University of Arizona at Tueson! the principal scientist for the Mars Reconnaissance Orbiter's high-resolution imaging experiment,

     Because liquid water is essential to life, the findings could have major implications for the possibility of Martianlife, There searchers said further exploration is needed to determine whether microscopic life exists on the planet.

    The presence of liquid water could also make life easier for astronauts visiting or living on Mars. Watercould be used for drinking and for creating oxygen and rocket fuel. NASA's goal is to send humans there inthe 2030s.

    The evidence of flowing water consistslargely of dark, narrow streaks(条痕) on the surface that tend to appear and growd uring the warmest Martian months and fade the rest of the year.

    Mars is extremely cold even in summer,and the streaks are in places where the temperature is as low as minus 10 degrees Fahrenheit. But salt can lower the freezing point of water and melt ice.

    The source of the water is a mystery. Scientists noted it could be melting ice. It could be an underground a quifer, which is rock or sand that can hold water. It is possibly water vapor from the thin Martian atmosphere, Or it may be a combination Michael Meyer, lead scientistfor NASA's Mars exploration program, said the only definitive way for now to determine whether there's life on Mars is to collect rocks and soil foranalysis on Earth - something a U.S. lander set for lift-off in 2020 will do.

B

    Asking for salary history provides an easy way to sort applicants into an employer's desired price range and helps the employer calculate the lowest offer that will still attract a candidate. But an increasing number of U.S. states and cities agree there ought to be a law against it. Massachusetts, Philadelphia, New York City and Puerto Rico have banned salary history questions on applications and in interviews.

    Why? Because when it comes to a candidate's suitability for a job, salary history is a subjective (主观的) and often misleading indicator — and it may most affect ＂the people who have already been illegally treated,＂ says Katie Donovan, a salary negotiation coach and one of the authors of the Massachusetts law.

    Candidates who start their careers underpaid because of the gender (性别) or race wage gap, a bad economy or a cheap boss finds that this lowball (虚报低价) figure continues to weigh them down throughout their career. At the same time, senior victims of layoffs have difficulty being hired because employers assume they're not interested in senior victims.

    In an interview, you can avoid talking about salary history questions by turning the discussion to what you're looking to make.

    Donovan recommends a method similar to what you're already doing: Enter $0.00, or some other number that is clearly intended not to cheat, but to oppose.

    Of course, there's always a risk doing so because it will cost you opportunities. But Ronda Wakefield, owner of NW MT HR Solutions, says that when she receives an application with an obviously false salary history, she'll still follow up if the candidate interests her. ＂I personally don't want to miss out on a great candidate because they didn't want to answer the question directly,＂ she says.

    Sunstroke (中暑) is a condition that can quickly go from dangerous to deadly, especially if proper care isn't given immediately.

    Sunstroke, sometimes called heatstroke, is a result of the body temperature rising above safe limits. This causes the body's necessary functions to stop working.

    It's usually pretty easy to avoid sunstroke, as long as proper action is taken. In that case, you need to act as quickly as possible to return that person's body to a safe temperature. Here are a few tips to help treat sunstroke.

Call for help

    Call to get an ambulance as quickly as possible. This should be the first thing you do, especially if the sunstroke person has fainted(昏倒). Also, call for help from anyone nearby if you're in a public place. If there's no one around, call someone nearby if they can get there sooner than an ambulance. Ask everyone to bring you as much water as possible, if there isn't much nearby.

Get the person to a cooler area

    If there's a building nearby, aim for that. Anywhere with plenty of air conditionings and water is perfect. If a building isn't available, bring the person to a well shaded area.

Get the water flowing

    If the person is still conscious, get him or her to drink water. If there's a bathtub available，fill it with cool water and put the person in it.

If your water supply is limited, you have to save it. Dampen a towel or shirt and put it on the person's body. Focus on the face, neck，and chest.

Fan the person

    Getting moving air over the person cools him or her down. Use anything, a towel or sheet, a shirt your hands，or a piece of board. This is where having many people around really helps, as they can combine to fan the entire body.

    In China, Double Eleven Shopping Day is approaching. And there is a similar case in the United States—Black Friday. It has been regarded as the beginning of the holiday shopping season. Although it's not an official holiday, millions of employers give their employees the day off, and many people use that day to get a jump-start on their holiday shopping. A similar day in Canada and Great Britain is called "Boxing Day".

    Black Friday has become somewhat of a marketing sensation in recent years. Since 2005, it has been the busiest shopping day of the year. To lure shoppers, retailers (零售商) routinely open their doors as early as 4 a.m. and offer special sales and promotions to the shoppers that arrive early. Some of the special deals offered by stores are only available in limited quantities. That is why some shoppers intent on getting the best deals often camp out in front of stores overnight so that they'll be the first in line when the doors open.

    But why is it called Black Friday? Historians believe the name started in Philadelphia in the mid-1960s. Bus drivers and police used "Black Friday" to describe the heavy traffic that would block city streets the day after Thanksgiving as shoppers headed to the stores.

    Businesses, however, didn't like the negative tone associated with the "Black Friday" name. In the early 1980s, a more positive explanation of the name began to circulate. According to this alternative explanation, Black Friday is the day when retailers finally begin to turn a profit for the year. In accounting terms (会计行业), operating at a loss is called being "in the red" because accountants traditionally used red ink to show negative amounts. Positive amounts were usually shown in black ink. Thus, being "in the black" is a good thing because it means stores are operating at a profit.

    Recently, for those who are too busy to shop on Black Friday or who just don't want to fight the crowds, the Monday following Black Friday has become known as Cyber Monday (网络星期一) for the many online deals.

    Looking out the window of his truck, Bob Fitzgerald sees large, undesirable plants growing in the fields. Visitors to his neighborhood around the Chesapeake Bay mainly see dying forests and empty farmland. Fitzgerald says the land has been in his family since the 17th century, and it has been sinking for hundreds of years. As sea levels rise salt water is entering rivers and other waterways. As a result, the ground is becoming too salty for crops to grow.

    Around the world, scientists warn that coastal (沿海 ) farms are under threat from rising seas and salt water. A World Bank report predicts that rice production in coastal areas may fall by 15 percent by the year 2050. Another study found that hundreds of millions of people will be forced to move inland because of rising waters.

    Kate Tully, an agroecologist(农业生态学家) wants to keep coastal farmers in business as the seas rise. The United States Department of Agriculture gave Tully and other researchers $ 1.1 million to study the problem. She and her team hope to give farmers ways to stay on their land. She told media that they are testing different crops on pieces of land around the coastal areas.

    "Sorghum is my new favorite crop because it can grow without rain and it can grow with lots of rain. So this is actually a pretty good option." The grain crop may be a good choice to feed the nearly 600 million chickens raised in the area each year. As farmers know, chickens can deal with salt, dry weather conditions and heavy rains. Tally's group is also testing other kinds of grain and a few crops that they believe can grow in the salt.

    Yet just being able to grow a crop is not enough. The crop has to be profitable. So an economist on the team will be looking at the numbers. But continuing to farm the land may not be the best plan of action. Some people believe the land should he given back to nature. They say the fields should be turned into wetlands, which are popular with duck hunters. "There's money in duck hunting," fully said. Hunting organizations will pay farmers for a permit to hunt on their land. Farmers could earn a lot of money from duck hunters, she said.

    Tully and her team are just getting started. It will be a few years before they really understand how to save the farms.