4 . Friendship needs care and attention to keep it in good health. Here are five ways to sustain (保持) long-distance friendships.

Long-lasting friendships share the characteristic that both sides equally contact (联系) and share with one another. With busy schedules, squeezing in phone calls can be a challenge.     1    .

Make sure you have communicated with your friend about how frequently each of you wants to be contacted and what method works best for you both.     2    . There are alternatives to constant written communication, such as leaving voice messages or having a group chat.

    3    . The friend who is remaining needs to be sensitive to all the additional time demands placed on the friend who has moved. The one in the new environment should be sympathetic to the fact that your friend may feel abandoned.

Anniversaries and birthdays carry even more weight in long-distance friendships. Although technology might make day-to-day communication possible, extra effort goes a long way on special days. Simply keeping a diary that keeps track of friends’ birthdays and other important dates will make sure nothing slips by you.

    5    , but long-distance friendships — even close ones — may require more conscious effort to sustain. Try to seek out chances to renew friendships. How to do it? Just spend face-to-face time together whenever possible.

6 . Goffin’s cockatoos, a kind of small parrot native to Australasia, have been shown to have similar shape-recognition abilities to a human two-year-old. Though not known to use tools in the wild, the birds have proved skilful at tool use while kept in the cage. In a recent experiment, cockatoos were presented with a box with a nut inside it. The clear front of the box had a “keyhole” in a geometric shape, and the birds were given five differently shaped “keys” to choose from. Inserting the correct “key” would let out the nut.

In humans, babies can put a round shape in a round hole from around one year of age, but it will be another year before they are able to do the same with less symmetrical (对称的) shapes. This ability to recognize that a shape will need to be turned in a specific direction before it will fit is called an “allocentric frame of reference”. In the experiment, Goffin’s cockatoos were able to select the right tool for the job, in most cases, by visual recognition alone. Where trial-and-error was used, the cockatoos did better than monkeys in similar tests. This indicates that Goffin’s cockatoos do indeed possess an allocentric frame of reference when moving objects in space, similar to two-year-old babies.

The next step, according to the researchers, is to try and work out whether the cockatoos rely entirely on visual clues (线索), or also use a sense of touch in making their shape selections.

In ancient China lived an artist    1     paintings were almost lifelike. The artist’s reputation had made him proud. One day the emperor wanted to get his portrait (画像) done so he called all great artists to come and present their     2     (fine) work, so that he could choose the best. The artist was sure he would    3    (choose), but when he presented his masterpiece to the emperor’s chief minister, the old man laughed. The wise old man told him to travel to the Li River～perhaps he could learn a little from the greatest artist in the world.

Filled with     4     (curious), the artist packed his bags and left.     5     he asked the villagers on the banks of the river where he could find the legendary (传奇的) artist, they smiled and     6     (point) down the river. The next morning he hired a boat and set out     7     (find) the well-known painter. As the small boat moved,     8     (gentle) along the river he was left speechless by the mountains being silently reflected in the water. He passed milky white waterfalls and mountains in many shades of blue. And when he saw the mists rising from the river and the soft clouds    9     (surround) the mountain tops, he was reduced to tears. The artist was finally humbled (谦卑) by the greatest artist     10     earth, Mother Nature.

9 . Molai grew up in a tiny village in India. The village lay near some wetlands which became his second___________. He learned the value and beauty of _________ there from a very young age.

When he was 16, Molai began to notice something _________ happening around his home. A flood had hit the area earlier that year and the _________ it caused had driven away a number of birds. _________, the number of snakes had declined as well. He _________ that it was because there weren’t enough trees to protect them from the _________. The solution, of course, was to plant trees so the animals could seek _________ during the daytime. He turned to the _________ department for help but was told that nothing would grow there. However, Molai went looking on his own and __________a nearby island where he began to plant trees.

________ young plants in the dry season was ____________for a lone boy. Molai built at the __________ of each sapling(幼树)a bamboo platform, where he placed earthen pots with small holes to____________ rainwater. The water would then drip(滴落)on the plants below.

Molai __________ to plant trees for the next 37 years. His efforts have resulted in 1,360 acres of naturally-grown land that has become home to many plants and animals.

The polar bear is found in the Arctic Circle and some big land masses as far south as Newfoundland. While they are rare north of 88°, there is evidence     1     they range all the way across the Arctic, and as far south as James Bay in Canada. It is difficult to figure out a global population of polar bears as much of the range has been     2    (poor) studied; however, biologists calculate that there are about 20,000-25,000 polar bears worldwide.

Modern methods     3     tracking polar bear populations have been employed only since the mid-1980s, and are expensive     4    (perform) consistently over a large area. In recent years some Inuit people in Nunavut     5    (report) increases in bear sightings around human settlements, leading to a     6    (believe) that populations are increasing. Scientists have responded by     7    (note) that hungry bears may be congregating(聚集) around human settlements, leading to the illusion(错觉) that populations are     8    (high) than they actually are. Of     9     nineteen recognized polar bear subpopulations, three are declining, six     10    (be) stable, one is increasing, and nine lack enough data.