I am peter Hodes ,a volunteer stem courier. Since March 2012, I've done 89 trips of those , 51 have been abroad, I have 42 hours to carry stem cells（干细胞）in my little box because I've got two ice packs and that's how long they last, in all, from the time the stem cells are harvested from a donor(捐献者) to the time they can be implanted in the patient, we've got 72 hours at most, So I am always conscious of time.

I had one trip last year where I was caught by a hurricane in America. I picked up the stem cells in Providence, Rhode Island, and was meant to fly to Washington then back to London. But when I arrived at the check-in desk at Providence, the lady on the desk said: “Well, I'm really sorry, I've got some bad news for you-there are no fights from Washington.” So I took my box and put it on the desk and I said: “In this box are some stem cells that are urgently needed for a patient-please, please, you've got to get me back to the United Kingdom.” She just dropped everything. She arranged for a flight on a small plane to be held for mere-routed(改道)me through Newark and got me back to the UK even earlier than originally scheduled.

For thiscourier job, you're consciously aware than that box you're got something that is potentially going to save somebody's life.

    In American schools there is something called Homecoming Day. Many high schools and colleges with a football team have a homecoming game. This can be the most important event of the year except graduation or commencement (毕业典礼)Day. Students plan Homecoming Day many weeks in advance.

    Several days before Homecoming, students start to decorate the school. There are signs to wish luck to the team, and many other signs to welcome all the graduates. Many people still come to Homecoming twenty or thirty years after their graduation.

    The members of school clubs build booths(售货棚）and sell lemonade(柠檬汽水), apples and sandwiches. Some clubs help to welcome visitors.

    During the day alumni and their wives will gather at the school. They like to look for teachers that they remember. Often they see old friends and they talk together about those happy years in school.

    Everyone soon comes to watch the football game. When the game is half over, the band comes onto the field and plays school songs. Another important moment is when the Homecoming Queen or King appears. All the students vote the most popular student Homecoming Queen or King. It is a great honor to be chosen.

    Homecoming is a happy day, but it is not perfect unless the football team wins the game. Even if the game loses, the students still enjoy Homecoming. Some stay at the school to dance, and others go to a party. For everyone it is a day worth remembering.

    London has become a cycle-friendly zone after the launch of a new bike hire scheme.{#blank#}1{#/blank#}

   {#blank#}2{#/blank#}First you have to sign up to the scheme to be sent a key. The key will unlock one of the bikes, which are kept at docking stations in and around central London. You have to pay an access fee for the key and then you pay as you go, for the length of time you use the bike.

    Transport for London, which runs the scheme, are hoping to have 6,000 bikes and 400 docking stations in place by the end of the year. {#blank#}3{#/blank#}London Mayor Boris Johnston launched the scheme and said London has been “filled with thousands of gleaming (发光的) machines that will transform the look and feel of our street and become as commonplace on our roads as black cabs and red buses”.

{#blank#}4{#/blank#} On the first day some people found they couldn't dock their bike properly and their usage of the bike had not registered. Transport for London did admit they had been expecting a few “teething problems” and have said they would not charge for the first day as a “gesture of goodwill”. Some other people have criticized the lack of docking stations and locks for the bikes as well as the price it costs to hire the bicycles.

    {#blank#}5{#/blank#}“My crusade for the capital to become the greatest big cycling city in the world has taken a great pedal-powered push forwards.”

A. So how does it work?

B. How do you like it?

C. However, there have been a few problems since the scheme was launched last Friday.

D. Despite the comments, the green-thinking London Mayor still says with certainty.

E. However, the London Mayor is confident of the scheme.

F. It has been designed to encourage more people to cycle in and around central London.

G. The new hire system is hoping to ease congestion(拥挤) in London and is expected to create up to 40,000 extra cycle trips a day into the city centre.

    Humans and many other mammals have unusually efficient internal temperature regulating systems that automatically maintain stable core body temperatures in cold winters and warm summers. In addition, people have developed cultural patterns and technologies that help them adjust to extremes of temperature and humidity (湿度).

In very cold climates, there is a constant danger of developing hypothermia, which is a life-threatening drop in core body temperature to below normal levels. The normal temperature for humans is about 37.0℃. However, differences in persons and even the time of day can cause it to be as much as 6℃ higher or lower in healthy individuals. It is also normal for core body temperature to be lower in elderly people. Hypothermia begins to occur when the core body temperature drops to 34.4℃. Below 29.4℃, the body cools more rapidly because its natural temperature regulating system usually fails. The rapid decline in core body temperature is likely to result in death. However, there have been rare cases in which people have been saved after their temperatures had dropped to 13.9-15.6℃. This happened in 1999 to a Swedish woman who was trapped under an ice sheet in freezing water for 80 minutes. She was found unconscious, not breathing, and her heart had stopped beating, yet she was eventually saved despite the fact that her temperature had dropped to 13.7℃.

In extremely hot climates or as a result of uncontrollable infections, core body temperatures can rise to equally dangerous levels. This is hyperthermia. Life-threatening hyperthermia typically starts in humans when their temperatures rise to 40.6-41.7℃. Only a few days at this extraordinarily high temperature level is likely to result in the worsening of internal organs and death.

    With its snow-covered mountains and a variety of wildlife, Yellow Stone National Park is one of the scenic treasures of the United States. Located primarily in Wyoming, the park hosts millions of visitors every year. If you plan to travel within the park, keep in mind advice from the National Park Service.

    Seasonal Travel

    Travel varies vastly from season to season. Roads are generally open in the summer except for cases of rock or mud slides, wild fires, accidents or road construction. Early snows in the fall can cause some roads to close temporarily. In the winter almost all roads are closed to motor vehicles, but snowmobiles and other snow vehicles with tracks are allowed. Roads begin to open for the spring by the latter part of April but can close if snowfall continues.

    Driving Time

    Grand Loop is the main road through Yellowstone National Park; it passes by most of the major attractions. These include Old Faithful, Yellowstone Lake and the Grand Canyon of Yellowstone. The maximum speed limit on the Grand Loop is 45 miles per hour, but the speed limit drops during some of the winding and twisting sections of this narrow road. Allow yourself at least two days to fully travel the loop due to the size of the park and being sometimes stuck in heavy traffic.

    Safety Awareness

    Buffalo(水牛)often block the roads in the park as they move through the fields. If a group is traveling across the road you are on  you can either wait for them to pass or find an alternative route. If you get out of your vehicle, the National Park Service says to stay at least 25 yards from any buffalo (and 100 yards or more away from bears and wolves). Buffalo are particularly unpredictable and charge people at speeds up to 30 mph.

    You can take your bicycle on any public roads and routes designed for bikes, but bicycles are not allowed on the park roads which are narrow with few shoulders. Altitudes range from 5, 300 to 8, 860 feet. The National Park Service recommends cyclists wear helmets and noticeable clothing.