Eco-tourism involves people travelling to beautiful but environmental sensitive place. Such trips are usually carried out with a(n) {#blank#}1{#/blank#} guide. Over recent years  this type of travel has been steadily gaining {#blank#}2{#/blank#} as more people search for new travel experiences.

    It is obvious that eco-tourism is beneficial in many aspects. First, all the money spent by the tourists is used to {#blank#}3{#/blank#} the important environmental spots they visit. Second, it helps visitors to better understand the environment, which is sure to {#blank#}4{#/blank#} their knowledge of the world. Furthermore, this style of travel is also more {#blank#}5{#/blank#} of the local culture.

    Compared to normal tourists, eco-tourist use energy more {#blank#}6{#/blank#}, save water and produce less rubbish by finding ways to recycle it. These behaviors have a(n) {#blank#}7{#/blank#} and lasting effect on the local environment.

    Two things are needed to make eco-tourism a success. First, it should be done in small groups. And second, because it requires {#blank#}8{#/blank#} effort, both eco-tourists and locals must be sincere in their devotion to improving the environment.

    Green travel provides local people with jobs in parks, hotels and shops. One great achievement of eco-tourism has been the {#blank#}9{#/blank#} of illegal hunting. Former hunters can now work as guides to help keep the animals safe in their natural surroundings.

Peru is one country using eco-tourism to promote respect for the environment. It's not able to take better care of its rainforests because of {#blank#}10{#/blank#} on more sustainable travel.

    In addition to this, local people's living-standards have improved. Many others are now following Peru's example and using eco-tourism to preserve their environment for the future generations.

Can a precise word total ever be known? No, says Professor David Crystal, known chiefly for his research in English language studies and author of around 100 books on the {#blank#}1{#/blank#}. "It's like asking how many stars there are in the sky. It's impossible to answer," he said.

An easier question to answer, he {#blank#}2{#/blank#}, is the size of the average person's vocabulary. He suggests taking a sample of about 20 or 30 pages from a medium-sized dictionary, which {#blank#}3{#/blank#} about 100,000 entries or 1,000 or 1,500 pages.

Tick off the ones you know and count them. Then {#blank#}4{#/blank#} that by the number of pages and you will discover how many words you know. Most people vastly underestimate their {#blank#}5{#/blank#}.

"Most people know half the words—about 50,000—easily. A reasonably educated person about 75,000 and a really cool, smart person well, maybe all of them but that is rather {#blank#}6{#/blank#}. An ordinary person, one who has not been to university say, would know about 35,000 quite easily."

The formula can be used to calculate the number of words a person uses, but a person's active language will always be less than their {#blank#}7{#/blank#}, the difference being about a third.

Prof Crystal says exposure to reading will obviously expand a person's vocabulary but the level of a person's education does not {#blank#}8{#/blank#} decide things. "A person with a poor education perhaps may not be able to read or read much, but they will know words and may have a very {#blank#}9{#/blank#} vocabulary about pop songs or motorbikes. I've met children that you could {#blank#}10{#/blank#} as having a poor education and they knew hundreds of words about skateboards that you won't find in a dictionary."