Lots of people stress out about talking in front of the class or getting laughed at if they make a mistake in front of an audience. {#blank#}1{#/blank#}The “stress hormones" that your body produces at times like these can actually help you focus.

    But when worry and stress about performing get to be too much, these hormones give people that “red alert(紧急状态)” feeling—the one that causes you to feel cold or sweaty, or get butterflies in your stomach. {#blank#}2{#/blank#}

    Be prepared. {#blank#}3{#/blank#} Rehearse(排练) as much as you can and practice in front of others at every opportunity. Most of all, think positively. Tell yourself “I'll be OK" or “I can do this" even if you are not 100% sure of it

    Look after yourself. Before big performances it's easy to let taking care of yourself slip as you spend too much time on rehearsals and practice. {#blank#}4{#/blank#} Exercise can also help you feel good, and along with sleep and nutrition, is an excellent way of keeping those stress hormones from getting out of control.

    Find out what the experts do. You can find books, DVDs, and online information about how to give your best when you perform, depending on what type of performance you're preparing for. {#blank#}5{#/blank#} Or ask the cast of your school play or your drama or music teacher how they beat stage fright. And if your parents or grandparents ever performed, they may have their own secrets to share.

    What is a big dream? {#blank#}1{#/blank#} Or, is a big dream something that provides only entertainment? Children dream big dreams, but there are three barriers to realizing dreams. They often kill them before they ever have a chance to grow.

The Self

    Immediately following the birth of a big dream, a negative self-talk takes over and gives all the reasons why it cannot happen. This inside voice is the ego (自我). It's there for protecting and should be listened to. {#blank#}2{#/blank#} Most people are influenced by the inside voice. That's why only a handful of people make their dream come true.

{#blank#}3{#/blank#}

    Family and friends are a lot like the ego. They want to protect those they love, so they will often list all the reasons why the big dreams won't come true. Sometimes, family and friends destroy dreams of those they love most, out of their own fear of being left behind.

The World

    If one gets past the first two barriers, one has to face the world.{#blank#}4{#/blank#} In the past, big dreamers were locked up and sometimes even killed when they were shown to the world. Fortunately, in most of the world today, big dreamers just get laughed at.

    The way to realize a big dream is with confidence and action. When children have confidence and then take action, they will be ready to accept any failure. The truth is that every great dreamer whose dreams have never seen the light of success knows failure well.{#blank#}5{#/blank#}

A. Family and Friends.

B. How big Dreams Die.

C. Does a big dream show one's future?

D. They simply fail until they succeed.

E. it is the last and the most terrible barrier.

F. Sometimes it is right, but more often it is wrong.

G. And their big dream is to be a rock star or a famous artist.

    So you want to be a citizen scientist? The National Science Foundation (NSF) has got you covered. NSF supports citizen science across all areas of science, whether your passion is to scan the night sky, or explore your own backyard.

Join a flock of birders

    eBird is an online platform that allows bird-watchers to go online and record their sightings to a database. With more than 100,000 active users, eBird's system is a treasure of information on bird population, distribution and habitat, which users can explore in real time.

Count every drop

    The Community Collaborative Rain, Hail and Snow Network (CoCoRaHS) is the largest provider of daily precipitation observations in the United States. Volunteers set up rain gauges and record data every time a rain, snow or hail storm passes over. Data is organized and shared on the CoCoRaHS website, and used by scientists, farmers and more.

Search for stars with your computer

    Einstein@Home uses your computer's idle time to search for space signals. The project has already had major successes: Volunteers discovered about 50 stars, using data from Puerto Rico's Arecibo Observatory and Australia's Parkes Observatory. Einstein@Home also searches for gravitational-wave signals using data from NSF's Laser Interferometer Gravitational Wave Observatory.

Be part of a supercomputer

    To link all those home computers, Einstien@Home uses software called the Berkeley Open Infrastructure for Network Computing, better known as BOINC. The software choreographs(安排，筹划) the technical aspect of volunteer computing and helps you use radio telescope signals to search for alien life.

Join the plankton party

    Without plankton, life in the ocean would not exist. These tiny organisms form the base of the food chain, and play an important role in the global carbon cycle. Plankton Portal enlists citizen scientists to identify images of plankton, snapped by the In Situ Icthyoplankton Imaging System (ISIIS), an underwater robot engineered at the University of Miami. ISIIS has taken millions of images in oceans around the world and upload them into a database; classifying the images helps researchers understand plankton diversity, habitat and behavior.

    Consider the tomato: easy to grow, healthy to eat, tasty in just about any dish and pleasant to look at. And come late summer, in steady supply. Though you can find it during the coldest winter months.

    August is the tomato's season to shine. Farmers' markets and stores are bursting with less known but tastier varieties, including purple cherries and big heirlooms.

    "Heirlooms ripened on the vine(藤) are the tastiest of all tomatoes," says Amy Goldman Fowler, author of The Heirloom Tomato. "I think their beauty is more than skin-deep." Heirloom seeds have been around for at least 50 years, often passed down from generation to generation. You may hear cherry or heirloom used to describe a tomato at hand, but there are many different kinds of tomatoes, and growers have fun giving fancy names to varieties: Mortgage Lifters, Beefsteaks, Oxhearts, Early Girls.

    And all of them come with health benefits. Tomatoes are a good source of the antioxidant lycopene (抗氧化番茄红素), which is thought to help lower a person's risk for heart problems and cancer. Tomatoes also contain healthy vitamins A and C. For the best fruit, choose tomatoes with shiny, firm skin and a little give, and store them at room temperature away from direct sunlight. Keep them out of the fridge, since cold temperatures can affect the original taste.

    "They satisfy something more than just taste," says Fowler. "Tomatoes feed your soul."

    The largest-ever study of the link between city walkability and high blood pressure has been considered as evidence of the "invisible value of urban design" in improving long-term health outcomes, say researchers. The study of around 430,000 people aged between 38 and 73 and living in 22 UK cities found significant connections between the increased walkability of a neighborhood and reduced risk of high blood pressure among its residents (居民).

    The results remained the same even after lifestyles and physical environment were changed, though the protective effects were particularly pronounced among participants aged between 50 and 60, women, and those living in heavily populated areas and poor neighborhoods.

    The paper was published in the International Journal of Hygiene and Environmental Health. With high blood pressure a major risk factor for chronic (慢性的) and particularly heart diseases, researchers at the University of Hong Kong and Oxford University said the findings showed the need to take notice of the health-influencing factor in urban design.

    "We are spending billions of pounds in preventing and curing heart diseases — if we are able to invest in creating healthy cities through small changes in the design of our neighborhoods to make them more activity-friendly and walkable, then probably, we will have significant savings in future healthcare expenses."

    Poorly designed spaces generally reduced walking and physical activity, promoting the lifestyles of long time sitting down and not moving, and were harmful to social communication, and as such related to poorer mental and physical health.

    Because walkability was “based on the potential (潜在的) design of the city", said Dr. Chinmoy Sarkar, cities could be adapted or designed to encourage it. “Such investments in healthy design are likely to bring in long-term gains as they are lasting and common."

The Harbourside Development is one of the world's most exciting places to shop. It's built right on the edge of Sydney Harbour, and there are over 200 shops, selling everything from home­made sweets to the very latest clothes in fashion; from Australian souvenirs to Swiss watches and Japanese cameras.

The Australian Wildlife Park has been specially built to give people an extra close look at Australia's native animals. Have your photo taken with a kangaroo，touch and feed koala bears. There are talks every afternoon about these animals, which are only found in this part of the world. There is also an excellent souvenir shop.

A visit to the Australian Museum is like an adventure across Australia. There are shows on the people and their way of life and the whole continent. Talks and guided tours help to make your visit unforgettable. There's also a café and a good book shop, selling excellent maps.

Taronga Zoo has Australia's finest collection of rainforest birds and sea­life centre which has many of the fish that can be found off the coasts of Australia and New Zealand. Taronga is also famous for its large group of South East Asian monkeys. Fast food can be got at cafés.