C

    Paul is a photographer(摄影师). He went to the Arctic to take pictures for NationalGeographic(《国家地理》). Finally, he saw a big and white polar bear swimming to him in the icy water.

    Paul lay down the ice to get a better photo, but the polar bear jumped out of the water and tried to attack him! Luckily for Paul, the ice cracked(破裂), or broke and the bear fell back into the water. The polar bear wasn't so lucky. It couldn't get a meal and had to swim farther away to find food.

    To understand the polar bear's problem, you need to know two things about the Arctic. First, the Arctic is mostly ocean(海洋). Second, ice covers(覆盖) a lot of the Arctic Ocean. In winter, the ice is thick, but in summer, the ice becomes thinner and breaks into pieces. Sea ice is the key to survival for Arctic animals. However, because of global warming, Arctic temperatures are rising and polar ice is melting(融化).

    Polar bears need ice  to hunt(捕捉) seals, their favourite meal. They stand on the ice and wait for the seals to come up for air. As Arctic ice melts, polar bears have to swim farther to find ice floes, or large pieces of floating ice. Sometimes, bears have to swim more than 200 km to find an ice floe. Some bears cannot swim that far and sadly they drown(淹死).

    On his last trip, Paul saw three dead bodies of polar bears. Before global warming threatened(威胁) Arctic ice, a dead bear was a rare sight. Paul is sad to see the dead bodies. Wildlife experts(专家) think global warming will have a terrible effect(影响) on polar bears. In the future, polar ice will continue to shrink and endanger the bears. Some scientists believe 65 percent of the world's polar bears will disappear(消失) by 2050. In other words, polar bears are in great danger.

    Is there intelligent(有智力的) life on other planets(行星)? For years, scientists said "No." or "We don't know." But today this is changing. Seth Shostak and Alexandra Barnett are astronomers (天文学家). They believe intelligent life exists somewhere in the universe. They also think we will soon contact these beings(人；生物).

    Why do Shostak and Barnett think intelligent life exists on other planets? The first reason is time. Scientists believe the universe is about 12 billion years old. "This is long enough for other planets to have intelligent life," say Shostak and Barnett. The second reason is size——the universe is huge. "Tools like the Hubble Telescope (哈勃望远镜) have shown that there are at least 100 billion galaxies (银河系) ," says Shostak. "And our galaxy, the Milky Way, has at least 100 billion stars. Some planets going around these stars might be similar to Earth. "

    In the past, it was hard to look for signs of intelligent life in the universe. But now, powerful telescopes (高倍望远镜) allow scientists to discover smaller planets--the size of Mars or Earth--in other solar systems (太阳系).These planets might have intelligent life.

    Have beings from space already visited Earth? "Probably not," says Shostak. "It's a long way away. However, intelligent beings may contact us in other way, such as radio signals(信号). "In fact, they may be trying to communicate with us now, but we don't have the right tools to receive their messages. However, this is changing. By 2025, we could make contact with other life forms in our universe and we might help each other.

①There's nothing quite like falling sound asleep after a full day or work. Like people, animals need to rest after working hard. Some animals sleep in water. Others dig holes under the ground. Some even sleep high in trees or under leaves. But they all find a way to rest.

②Some animals in the sea sleep in strange ways. Fish sleep with their eyes open. They seem to look ahead far into the sea while they rest. Sea otters sometimes sleep in beds of the plants that grow in the sea. This keeps them from moving away. Parrotfish blow something from their mouths when they are ready to sleep. Then a bubble(气泡) will be formed around them. The bubble protects them from harm while they sleep.

③Some animals sleep under the ground. Chipmunks(花栗鼠) sleep curled up in a ball. Their beds are made of grass. In winter, they sleep for two weeks before waking up again. Some desert frogs di g underground holes during the hot, dry season. A frog may stay in its hole for months.

④There are some animals who sleep in the air. Some seabirds can sleep while they fly. These large birds spend most of their lives over the ocean. They are in danger on the water, but they are safe in the air. They glide for many hours without flapping(拍打) their wings.

⑤High above the ground, monkeys find leafy places in trees each evening before they sleep. The tall trees help to keep monkeys safe during the night. Some insects even sleep under the leaf that will be their next meal. A bee may climb down into a flower to rest. When it climbs out the next morning, it is rested and ready for work.

A few years ago,I visited theclassical gardens of Suzhou. During the visit, my attention {#blank#}1{#/blank#}(draw) away from the plants, bridges and stones, towards {#blank#}2{#/blank#} walls of the gardens. Mostly white, some parts of the walls are losing small {#blank#}3{#/blank#}(piece) of their coverings.

 This creates space in which light and plants can be seen. The walls are not only the boundaries of the gardens, but they also form protected roads {#blank#}4{#/blank#} guide you on a trip.

 The memory of the white walls stayed with me. I kept imagining how many shadows(影) could be collected {#blank#}5{#/blank#} them to dance with the light. This fantastic moment was so {#blank#}6{#/blank#} (live) that I came back to explore with my camera.

{#blank#}7{#/blank#}(walk) freely with these walls and their marks, I began to feel like collecting all the stories that {#blank#}8{#/blank#}(be) painted there. Weather and time have turned these amazing white walls into Chinese landscape paintings.

I {#blank#}9{#/blank#}(take) the photos during the month of June, just after the rain. The air was full of small   drops of water, showing the light and the color of the things around. As color was born out of a dance between light and a body, when photographing in color I found {#blank#}10{#/blank#}(I) enjoying a moment of this dance.

Dragon Boat Festival is a fun Chinese holiday. Usually, it's in June or July. Both children and adults like this holiday.

First, there are dragon boat races. Dragon boats are very long. They have bright colours, In each boat, there are many people rowing(划) . There's also somebody beating a drum. The winners of the races can get a lot of money.

During Dragon Boat Festival, people also eat a special kind of food-- rice dumplings. To make these dumplings, people prepare (准备) many things. Then they can make different flavors of dumplings. Some are sweet, some are salty (咸的) . They all taste good. People give them to friends.

On the evening of the holiday, families have a big meal together. Dragon Boat Festival is a great time for everybody.