To prevent the deserts coming near, China has planted billions of trees—to replace destroyed forests and as barriers against the sand. This isn't a cure, though, say experts, as thirsty trees can make the problem worse by taking in groundwater.

    “Planting tress is one way, but it isn't that simple. It doesn't solve the basic issue of water resources,” says Wu Bo, a professor. “We need to calculate how much water the trees will absorb, or else it could have a negative effect.”

    Villagers in Zhengxin have taken on this challenge, with limited success. When the irrigation channels began to run dry, Lu Xianglin switched from wheat to cotton on his land. He also planted trees to protect his fields from sandstorms. He says he still gets good yields（产量） using flood irrigation and earns a good income for his family.

    Other farmers haven't stuck it out（坚持到底）: about one in three have left Zhengxin in the past 10 years after their wheat crops died. Young people who can find jobs in the towns rarely return.

    Last week, Mr Lu joined the other men in his village on a government-arranged trip to see the land that has been set aside for their relocation, nearly 40 miles to the south. The next day, he was back, shaking his head at the plan. The idea of uprooting his family troubles him, as does the idea of giving up the land that fed his forefathers. He prefers to stay and keep up the fight.

    “With enough water, this problem can be solved,” Lu says. “We can plant trees and grass, and they will grow bigger. That will stop the desert.”

    Experts say that farmers could switch to drip irrigation （滴灌）to lessen their water intake for growing crops. Elsewhere in the region, farmers have built brick greenhouses as part of a plan to grow vegetables using less water. Roadside signs urge farmers to “Save Water, Protect the Environment”.

    On the arrival of the graduation season, a large number of students will leave their colleges and get busy finding jobs. However, it seems not all students will be in a hurry to get to work. According to a survey online in May, about 9.8 percent of the 93,420 graduates surveyed said they wouldn't begin working right after graduation. This phenomenon is called "delayed employment".

    One reason why the graduates don't start their careers immediately is that they want a job related to their personal interests, and they are unwilling to give in and take jobs they don't like. "Looking for the right career is like looking for Mr. Right. Maybe I could have found a job or two, but I don't want to just make a living or be stuck in a specific position,” said Shen Yu, who graduated in 2014 but didn't look for a job right away.

    Another reason is to avoid the fierce competition of the job market.Statistics provided by the Ministry of Education show the number of the new university graduates will reach 7.95 million this year. Meanwhile, only 26.7 percent of the new graduates have signed contracts(合同) with employers, 8.7 percent down from the previous year.

    And some Chinese college students have chosen to travel or volunteer instead of finding jobs. For example, Chen Nuan, who will graduate from the Shanghai Institute of Visual Arts this summer, has planned to tour Europe immediately after graduation. "As the old Chinese saying goes,traveling thousands of miles is better than reading thousands of books,"she told China Daily.

    However, no matter what you choose after graduation, make full use of the first few years—this is when people develop soft skills such as punctuality and teamwork. The first 10 years are essential, which shapes careers in the long term.

    For years,Hagelin has studied what role scents（气味）play in wild birds' behavior.In 2010,Hagelin heard Jan Straley,a marine biologist,talk about the behavior of whales.Straley mentioned that whales often leap into the air,but nobody knew why.

    The mystery interested Hagelin.So Hagelin asked Straley whether they might leap to smell the air—maybe to locate food or look for danger.Straley replied that it was an interesting idea but there wasn't much evidence that whales have a sense of smell.To investigate the idea further,the two scientists teamed up.

    In the summer of 2011,they set up a post on the coast of southern Alaska.The researchers spent hours monitoring the direction of the whales and of the wind.The whales headed into the wind half of the time.This didn't prove that whales leap to smell,but it suggested that it is possible.

    Meanwhile,other researchers in Alaska were studying a region of the brain called the olfactory bulb（嗅觉球）in whales.Olfaction means the ability to smell.Humans also process smells in the olfactory bulb.

    In identifying a scent,you might think the nose does all of the work.However,the major role of a nose is to draw chemicals on the air and pass them across sensing cells.As chemicals come into contact,they give signals that travel directly to the bulb and then in the brain for further interpretation.

    The researchers discovered that the bulb in a whale was more complex than the one in a human.In whales,this smell-processing center takes up a share of the brain six times larger than it does in humans.

    The brain research suggested that whales probably can smell just as well as people—and possibly better than humans can.It is supposed that a good sense of smell could help them find food more easily.

    However,Hagelin is not sure of that.Now he is planning a new study that will examine whether whales do use the sense of smell to find food.

    Navajo was the perfect choice for a secret language. It is very complex. One vowel (元音）can have up to ten different pronunciations, changing the meaning of any word. In the 1940s, Navajo was unwritten language. No one outside of the reservation could speak it or understand it.

    The Navajo Code team had to invent new words to describe military equipment. For example, they named ships after fish: lotso-whale (battleship), calo-shark (destroyer), beshloiron-fish (submarine). When a Code Talker received a message via radio, he heard a series of unrelated Navajo words. He would then translate the words into English and use the first letter of each English word to spell the message. The Navajo words tsah (needle), wol-la-chee (ant), ah-kh-di-glini (victor), and tsah-ah-dzoh (yucca) spelled NAVY.

    The Code Talker kept the code a secret. They memorized everything. There were no code books. As a result, no ordinary Navajo soldiers, if captured by the enemy, could understand the code. More than 3,600 Navajos served in World War II, but only 420 were Code Talkers with the US Marines. They coded and decoded battlefield messages better and faster than any machine. They could encode, transmit, and decode a three-line English message in 20 seconds. Machines of the time required 30 minutes to perform the same job.

    Even after the war the code remained top secret. When they were asked about their role, Code Talkers just said: “I was a radioman.” War movies and histories came out without mentioning them. The code was never used again and was finally declassified in 1968. Only then did the secret came out.

    San Francisco is a wonderful vacation destination that offers many different things to see and to do. The best way for a traveler to get a feel for the city is to take one of the many different tours there.

    Foot. When touring the city by walking, you aren't going to walk much. There are far more benefits to touring the city on foot, though. This kind of tour allows you to see many of the buildings. It usually makes you see a more localized neighborhood level.

    Water. The waters of San Francisco Bay have played an important role in the city's development over the last century. Touring San Francisco by water is a completely unique way for you to see this wonderful city.

    Bus. If you want to get a great feel for the layout of the city, one of the best things you could do is book a tour through our company. A bus tour of San Francisco is one of the most complete ways to experience the city.

    Air. While it is the most expensive way to see San Francisco, it is also one of the most unique and thrilling ways to see the city. Seeing the city from high above allows you to get a good feel for the layout of the city as tour guides point out landmarks and attractions. If you decide to tour San Francisco from the air, you'll get memories that you won't forget forever.

    We are a travel agency with good service. For more information, please click here.

    Societies all over the world name places in similar ways. Quite often there is no official naming ceremony but places tend to be called names as points of reference by people. Then an organized body steps in and gives the place a name. Frequently it happens that a place has two names: One is named by the people and the other by the government. As in many areas, old habits died hard, and the place continues to be called by its unofficial name long after the meaning is lost.

Many roads and places in Singapore(新加坡) are named in order that the pioneers will be remembered by future generations. Thus we have names such as Stamford Road and Raffles Place. This is in keeping with traditions in many countries — in both the West and the East.

Another way of naming places is naming them after other places. Perhaps they were named to promote friendships between the two places or it could be that the people who used to live there were originally from the places that the roads were named after. The mystery is clearer when we see some of the roads named in former British bases. If you step into Selector Airbase you will see Piccadilly Circus — obviously named by some homesick Royal Air Force personnel.

    Some places were named after the activities that used to go on at those places. Bras Basah Road is an interesting example, "Base Basah" means "wet rice" in Malay(马来语). Now why would anyone want to name a road "Wet Rice Road"? The reason is simple. During the pioneering days, wet rice was laid out to dry along this road.

    A few roads in Singapore are named by their shapes. There is "Circular Road" for one. Other roads may have part of their names to describe their shapes, like "Paya Lebar Crescent". This road is called a crescent (月牙) because it begins on the main road, makes a crescent and comes back to join the main road again.