When we can see well, we do not think about our eyes very often. It is only when we cannot see perfectly that we come to see how important our eyes are.

    People who are nearsighted can only see things that are very close to their eyes. Many people who do a lot of close work, such as writing, reading and sewing（缝纫）, become nearsighted. Then they have to wear glasses in order to see distant things clearly.

    People who are farsighted（远视的）suffer from just the opposite problem. They can see things that are far away, but they have difficulty reading a book unless they hold it at arm's length. If they want to do much reading, they must get glasses too.

    Other people do not see clearly because their eyes are not exactly the right shape. This, too, can be corrected by glasses. Some people's eyes become cloudy because of cataracts（白内障）. Long ago these people often became blind. Now, however, it is possible to operate on the cataracts and remove them.

    When night falls, colors become fainter to the eye and finally disappear. After your eyes have grown used to the dark, you can see better if you use the sides of your eyes rather than the centers. Sometimes, after dark, you see a small thing to one side of you, which seems to disappear if you turn you head in its direction. This is because when you turn your head, you are looking at the thing too directly. Men on guard duty sometimes think they see something moving to one side of them. When they turn to look straight at it, they cannot see it any more, and they believe they were mistaken. However, this mistake happens because the center of the eye, which is very sensitive(敏感的) in daylight, is not as sensitive as the sides of the eyes after dark.

    Lost cities that have been found

    The White City

    In 2015, a team of explorers to Honduras in search of “the Lost City of the Monkey God” led to the discovery of the White City. They found the ruins in the Mosquitia region of the Central American country — which is known for poisonous snakes, vicious jaguars and deadly insects. It is believed that local people hid here when the Spanish conquerors(征服者)occupied their homeland in the 16th century.

    Canopus and Heracleion

    Modern researchers were teased by the ancient writings about the Egyptian cities Canopus and Heracleion — where Queen Cleopatra often visited. But the cities weren't found until 1992, when a search in Alexandria waters found that the two cities had been flooded for centuries. Artifacts(史前器物)showed that the cities once highly developed as a trade network, which helped researchers piece together more about the last queen of Egypt.

Machu Picchu

    A Yale professor discovered “the Lost City in the Clouds” in 1911. A combination palaces, plazas, temples and homes, Machu Picchu displays the Inca Empire at the height of its rule. The city, which was abandoned in the 16th century for unknown reasons, was hidden by the local people from the Spanish conquerors for centuries, keeping it so well preserved.

Troy

    The ancient city of Troy in Homer's The Iliad was considered a fictional setting for his characters to run wild. But in 1871, explorations in northwestern Turkey exposed nine ancient cities layered(层叠)on top of each other, the earliest dating back to about 5,000 years before. It was later determined that the sixth or seventh layer contained the lost city of Troy and that it was actually destroyed by an earthquake, not a wooden horse.

    Discover Nature Schools programs

    Becoming Bears (Kindergarten-2 grade)

    By becoming baby bears children learn from their "parent" to survive the seasons. Kids will find safety in the spring and learn kinds of food bears eat during the summer, and then create a cave for winter hibernation(冬眠). After learning the skills needed to survive, students will go out of the cave as an independent black bear able to care for themselves. (1.5-2 hours)

    Whose Clues? (3-5 grade)

    Kids will discover how plants and animals use their special structures to survive. Through outdoor study of plants and animals, kids will recognize their special structures and learn how they enable species to eat, avoid their enemies and survive. Using what they have learned, kids will choose one species and tell how they survive in their living places. (3-4 hours)

    Winged Wonders (3-5 grade)

Birds add color and sound to our world and play an important ecological (生态的) role. Students will learn the basics of birds, understand the role birds play in food chains and go bird watching using field guides and telescopes. Students will do hands-on activities. Students will use tools to build bird feeders, allowing them to attract birds at home.(3-4 hours)

Exploring Your Watershed (6-8 grade)

    We all depend on clean water. Examining how our actions shape the waterways around us. Go on a hike to see first-hand some of the challenging water quality problems in a city. Students will test the water quality to determine the health of an ecosystem.

    Each program is taught for a class with at least 10 students.

    All programs include plenty of time outdoors. So please prepare proper clothing, sunscreen and insect killers for children.

    To take part in a program, please email dcprograms@mdc.mo.gov.

The Nautilus Expedition(探险) to the Cayman Islands

Hi! I'm Talita and this is my blog! Enjoy!

Day 1: August 15^th

Wow! I can't believe I'm actually here on Nautilus. I'm one of five very lucky students chosen to go on Nautilus's four-day expedition to the Cayman Islands. We had a talk from the expedition leader Dr. Katy Croff Bell about where we're going and what we'll be doing. Oh, and all the safety rules as well, of course!

Day 2: August 16^th

What an amazing day! In the morning, we met Dr. Robert Ballard, who discovered the wreck(残骸) of the Titanic! After lunch, we had a tour around Nautilus. We looked at the labs, and we went up to the bridge—that's where the captain of the ship works. I even got a chance to guide the ship! Later we learned about Hercules. This robot is sent deep into the sea to look for shipwrecks, to study the plants and animals, and to look at the rocks in an area.

Day 3: August 17^th

This morning we appeared on the Nautilus Live website and talked to students around the world about our expedition. It was amazing—I feel like a real famous person now! The afternoon was NOT cool, however. There was a big storm , and we all felt very seasick!

Day 4: August 18^th

This morning was beautiful, and the sea was peaceful. Perfect for a dive. Unfortunately, it was Hercules, not us, who got to go diving. In the afternoon, we arrived at Grand Cayman. Although I'm sad to leave the Nautilus team (especially Hercules), I'm excited to explore the islands and the waters!

While wandering around a Swedish Christmas market, you'll likely come across booths {#blank#}1{#/blank#} (sell) carved wooden horses, typically in an assortment of bright colors and floral patterns. These {#blank#}2{#/blank#} (tradition) Swedish toys are much more than a classic holiday gift or travel souvenir: the Dala horse has become intertwined (交织) with the very image of Sweden {#blank#}3{#/blank#}.

The little wooden horses of Sweden were originally carved by men that worked in the forests during {#blank#}4{#/blank#} winter. When they returned to their villages, they gave the horses to children as playthings. This was in the 17^th century during {#blank#}5{#/blank#} the horses were also sold at market in small towns and villages in the Dalarna region, in central Sweden. The horses were painted in bright colors that were inspired by the furniture in the region. {#blank#}6{#/blank#} (eventual) , even young children learned to carve wooden horses. 

The global attention didn't come until the 20 ^th century in the World's Fair in New York 1939. That was because an enormous painted Dala horse was placed outside the Swedish pavilion, which caused excitement throughout the crowds of {#blank#}7{#/blank#} (visit) . After this, the Dala horses were seen {#blank#}8{#/blank#} a symbol of Sweden and mass production of the horses started. Since then, Dala horses {#blank#}9{#/blank#} (be) popular souvenirs and inspired other products as well. You can now find anything from clothing to tableware and phone cases with a Dala horse {#blank#}10{#/blank#} (decorate) .

 Knowledge is power, and the more you learn about mental health, the better the position you may be in to help those facing mental health battles. Consider doing the following things to support those closest to you.

 Attend a training course

{#blank#}1{#/blank#}. In fact, anyone can benefit from depression awareness training that focuses on supporting those at risk. You might be a teacher that manages youth or a sports coach wanting to pick up on depression risk signs in your players. You may even be a worried parent who wants to make sure your children can tell you anything. Depression awareness and prevention courses teach you both theoretical and practical skills to recognize warning signs and behaviors. {#blank#}2{#/blank#}.

 Listen

 If someone approaches you in their time of need, it's not always easy to know what you' re supposed to do, and it may be more beneficial for you to just listen. {#blank#}3{#/blank#}. They may just need to get what they are feeling off their chest and to feel valid at that moment. Try your best not to interrupt, but ask questions if you require clarification. The more listening you do, the better your position in deciding what to do next.

{#blank#}4{#/blank#}.

 While being a listening ear is sometimes all. someone needs to feel better, you can also become an ongoing source of support. Check in with the person experiencing a mental health problem like depression so that they know you are always there for them. Make contact with them regularly to see how they are feeling. Just knowing someone cares can make a world of difference.

 Call emergency services

 Your support, guidance, and listening ear can be of great value to anyone going through a tough time. {#blank#}5{#/blank#}. If someone you know is experiencing self- abuse thoughts or tendencies, don't delay in seeking emergency help. The faster you act, the safer your friend or family member may be.

A. Check in with them

B. Suggest support services

C. However, it's essential to know your limits

D. Such a course may just help you to prevent someone's depression

E. They may not need you to offer solutions or even give them a hug

F. Sometimes, the best thing you can do is encourage them to seek professional help

G. You don't have to be in a professional health role to attend depression prevention training