A new study warns that about thirty percent of the world's people may not have enough water by the year 2025.

    A private American organization called Population Action International did the new study. It says more than 335 million people lack enough water now. The people live in 28 countries. Most of the countries are in Africa or the Middle East.

    P-A-I researcher Robert Engelman says by the year 2025, about 3,000 million people may lack water. At least 18 more countries are expected to have severe water problems. The demand for water keeps increasing. Yet the amount of water on the earth stays the same.

    Mr. Engelman says the population in countries that lack water is growing faster than in other parts of the world. He says population growth in these countries will continue to increase.

    The report says lack of water in the future may result in several problems. It may increase health problems. Lack of water often means drinking water is not safe. Mr Engelman says there are problems all over the world because of diseases, such as cholera, which are carried in water. Lack of water may also result in more international conflict. Countries may have to compete for water in the future. Some countries now get sixty percent of their fresh water from other countries. This is true of Egypt, the Netherlands, Cambodia, Syria, Sudan, and Iraq. And the report says lack of water would affect the ability of developing to improve their economies. This is because new industries often need a large amount of water when they are beginning.

    The Population Action International study gives several solutions to the water problem. One way, it says, is to find ways to use water for more than one purpose. Another way is to teach people to be careful not to waste water. A third way is to use less water of agriculture.

    The report also says long-term solutions to the water problem must include controls on population growth. It says countries cannot provide clean water unless they slow population growth by limiting the number of children people have.

New York City Tour Guide

CENTRAL PARK PHOTO TOUR $79

With Sam L.

    Come to shoot in the Central Park of New York that will allow you to take home digital postcards.This tour is a great introduction to Central Park and combines views of the bridges,lakes and skyline.

    At each stop of the photo tour,I will provide you with explanations around photography（摄影）,camera settings, etc.You will be able to put these tips to good use immediately.

NEW YORK RUNMNG TOUR $50

With Sebastien B.

    Love running?Love New York?Do you want to see the sites of the city?Contact me and we'll take a special tour. All you'll need to do is to put on your sports shoes and we'll be off.I'll show you my favorite running spots along the Hudson River or north of Central Park and away from all the tourists.

    If you're thinking of training for something,I'll give you the explanations and tips to make the best of your time training!

GREENWICH VILLAGE FOOD TOUR $75

With Manhattan W.

    Discover unbelievable places to eat.This is the real Greenwich Village gastronomic（美食的）experience.Along the way,find out how the village has kept its unique character throughout the years,from the Dutch and English controlled periods to today.

Tour runs every day from 12:30 PM-2:30 PM.

NEW YORK BY NIGHT PHOTO TOUR $115

With Sam L.

    We have already prepared NYC for the most unique points for you.During the  hour walking tour,we share these special comers of NYC.

    The night tour teaches night photography techniques while discovering the "darker" side of the city that never sleeps: the UN headquarters,42nd street,Grand Central Terminal,the Chrysler Building,Rockefeller Center and Radio City Music Hall.

    The best bikes for the beginners

    When it comes to purchasing your first bike, the choice is endless, making it tough to know what to go for. Here are the the best buys on the market right now.

⒈Boardman Cx Comp

    This is a cross country bike, and it's so multifunctional that you can handle any terrain(地势) on it , making it a great choice for those wanting to try various cycling subjects. If you leave on the thick tires it comes with, it can ride on various paths and can even handle some less demanding mountain bike routes. Alternatively, put on thin, smooth tires and treat it asa road bike. It has a basket and comes with Shimano Sora gears (变速器), which are outstanding for its price.

£650, Halfords

⒉Planet X RT-58 v2

    Planet X is based in Yorkshire, which means you'd probably have to buy this bike without seeing it. But it's worth it，because this is an excellent machine at a lower price, Planet X is a highly rated manufacturer and this model comes with Shimano Sora gearing.

£585, Planet X

⒊Specialized Allez E5

    Specialized is one of the biggest and most popular brands in cycling, and this is its hugely popular primary road bike. It comes with solid components from front to back and you'll look great out on the road.

£ 75, Evans Cycles

⒋Boardman Road Team Carbon

    If you can push your budget further still, this bike is worth the extra investment. The frame is made entirely from carbon, which is lighter, faster and more comfortable than the composition metal models above and gives you an all round and more enjoyable ride. It also means that if you get really serious about cycling, you don't have to upgrade as quickly as you would with a cheaper bike.

£800, Halfords

    Very few people enjoy going to the dentist, especially for a filling. Often fillings need to be replaced during the patients' lifetime. But is filling the cavity (蛀洞)with a foreign material really the best treatment? What if the tooth could repair itself with its own material–dentine(齿质)? Researchers at King's College London have found a process that may replace the traditional method.

    Paul Sharpe of King's College says a new treatment for cavities is simpler. It uses a drug that causes the tooth to fill in the hole naturally with dentine. "It involves putting a drug in the hole. It excites a natural process, which starts to occur anyway following the damage, so you can actually get the big hole repaired and the repair is a production of the natural material, the dentine."

    Usually a new drug requires repeated testing before it is approved for treatment. However, this drug that produces the re-growth in teeth has already been approved. It is a drug used to treat Alzheimer's disease and other disorders of the nervous system. Researchers explain that they use only a small amount and they use it locally. Usually that means the medicine is put directly on the affected area. It does not travel through the patient's blood.

    Nigel Carter heads Britain's Oral Health Foundation. He describes the new treatment as an exciting possibility for dental care. But Carter also has a warning. "Actually re-growing the tooth that has been lost with a cavity would be really a huge step forward. But, it's also important that we remember that we shouldn't be getting the cavity in the first place. We're talking about a totally preventable disease."

Larry was on another of his underwater expeditions(探险)but this time, it was different. He decided to take his daughter along with him. She was only ten years old. This would be her first trip with her father on what he had always been famous for.

    Larry first began diving when he was his daughter's age. Similarly, his father had taken him along on one of his expeditions. Since then, he had never looked back. Larry started out by renting diving suits from the small diving shop just along the shore. He had hated them. They were either too big or too small. Then, there was the instructor. He gave him a short lesson before allowing him into the water with his father. He had made an exception. Larry would never have been able to go down without at least five hours of theory and another similar number of hours on practical lessons with a guide. Children his age were not even allowed to dive.

After the first expedition, Larry's later diving adventures only got better and better. There was never a dull moment. In his black and blue suit and with an oxygen tank fastened on his back, Larry dived from boats into the middle of the ocean. Dangerous areas did not prevent him from continuing his search. Sometimes, he was limited to come to a cage underwater but that did not bother him. At least, he was still able to take photographs of the underwater creatures.

    Larry's first expedition without his father was in the Cayman Islands. There were numerous diving spots in the area and Larry was determined to visit all of them .Fortunately for him, a man offered to take him around the different spots for free. Larry didn't even know what the time was, how many spots he dived into or how many photographs he had taken. The diving spots afforded such a wide array of fish and sea creatures that Larry saw more than thirty varieties of creatures.

Larry looked at his daughter. She looked as excited as he had been when he was her age. He hoped she would be able to continue the family tradition. Already, she looked like she was much braver than had been then. This was the key to a successful underwater expedition.

    When you are sitting in the car, do you ever notice the drivers looking over their shoulders or side to side in the car? Well, they are doing this to check their blind spots! Blind spots make driving extremely difficult and increase the potential for car accidents.

    Fourteen-year-old Alaina Gassier from Pennsylvania noticed her mother struggling with blind spots while driving their family car. So she came up with an ingenious solution that won the first place and $ 25,000 in the Broadcom Masters Competition.

    Blind spots are the areas around the car that cannot be directly observed by the driver. There are two kinds of blind spots-on the back of the car that cannot be seen with mirrors, and blind spots at the front of the car as well.

    When a driver is changing lanes, he has to look over his shoulder through the side windows to make sure that there is no vehicle in the blind spot. This invisible area is big enough to hide a car!

    The other blind spot is created in the front by the A-pillar(柱子)-the material on either side on the windshield(挡风玻璃)that holds the glass and forms the frame of the car. In some cars, this pillar can be quite thick. Usually, people or cyclists can be hidden by this pillar.

    Alaina's design was to get rid of the blind spot created by the front A-pillar of the car, the one that helps hold up the windshield.

    She put a camera on the outside passenger side of the car which then sent the photos to a projector above the driver's head. Then, she covered the inside of the pillar in a reflective fabric onto which the image was projected. Basically, her device made the pillar "see through" and removed the blind spot on that side of the car.

    Alaina's solution is very creative and could be improved by using LCD displays that will make it easier to see during day time as well.