1 . Endangered polar bears are breeding (繁殖) with grizzly bears (灰熊), creating “pizzly” bears, which is being driven by climate change, scientists say.

As the world warms and Arctic sea ice thins, starving polar bears are being forced ever further south, where they meet grizzlies, whose ranges are expanding northwards. And with that growing contact between the two come increasing hybrids (杂交种).

With characteristics that could give the hybrids an advantage in warming northern habitats, some scientists guess that they could be here to stay. “Usually, hybrids aren’t better suited to their environments than their parents, but these hybrids are able to search for a broader range of food sources,” Larisa DeSantis, an associate professor of biological sciences at Vanderbilt University, told Live Science.

The rise of “pizzly” bears appears with polar bears’ decline: their numbers are estimated to decrease by more than 30% in the next 30 years. This sudden fall is linked partly to “pizzly” bears taking up polar bears’ ranges, where they outcompete them, but also to polar bears’ highly specialized diets.

“Polar bears mainly consumed soft foods even during the Medieval Warm Period, a previous period of rapid warming,” DeSantis said, referring to fat meals such as seals. “Although all of these starving polar bears are trying to find alternative food sources, like seabird eggs, it could be a tipping point for their survival.” Actually, the calories they gain from these sources do not balance out those they burn from searching for them. This could result in a habitat ready for the hybrids to move in and take over, leading to a loss in biodiversity if polar bears are replaced.

“We’re having massive impacts with climate change on species,” DeSantis said. “The polar bear is telling us how bad things are. In some sense, “pizzly” bears could be a sad but necessary compromise given current warming trends.”

3 . For people suffering from depression, there’s an all-natural treatment they should use — getting more exercise. It could help fight depression, even if people have a genetic risk, new research shows.

For the study, researchers collected information from nearly 8,000 people and found those with related genes were more likely to have depression over the next two years after examining them. But that was less likely for people who were more active at the study’s start, even if they had a family history of depression. Higher levels of physical activity helped protect even those with the highest genetic risk of depression.

Both high-intensity (高强度) exercise and low-intensity activities were associated with a reduced risk of depression. Adding four hours of exercise a week could lower the risk of a new episode (一段经历) of depression by 17%, according to the study. “Our findings strongly suggest that, when it comes to depression, being physically active has the potential to remove the added risk of future episodes in individuals who are genetically risky,” said lead author Karmel Choi. “On average, about 35 additional minutes of physical activity each day may help people to reduce their risk and protect against future depression episodes.”

Depression is a common mental illness globally, with more than 264 million people affected. “Depression is so ubiquitous, and that underlines the need for effective approaches that can impact as many people as possible,” Choi said. And mental health and primary care providers can use the findings to advise patients that there’s something meaningful they can do to lower their risk of depression.

5 . I’ve heard that it’s better to give than to receive. But I’m here to tell you that the ________ of receiving should never be under estimated (低估).

I was nine when my Dad and Mom ________, and took me to my grandparents. I decided at that age, in my loneliness and anger that I’d become unbelievably ________, needing no one.

Believe it or not, I took care of everyone in my life, even when I was in worse shape. Once in a while, ________, someone would do something for me at just the moment.

Once, when I was a single parent, I took my son to see Santa Claus.

When he ________ me to buy the photo that was taken, I opened my wallet, only to find that I didn’t have enough money. When I got to the counter to ________ the photo, I was told that someone inline ahead of me had seen me ________ my change and had paid for me. I rushed out to thank the person whose small kindness ________ so much. I found no one in sight. I wanted to ________ that I didn’t need this and I just didn’t have enough cash on that day. I ________ then that it’s okay. It’s okay to let someone do something for me, ________ I could have done it myself.

I have received the blessings (祝福) of those whose acts of generosity and_______ have found me when I needed them most. I believe that it’s not about my strength and independence. It’s about allowing the giver to be blessed when the gift is graciously (优雅地) ________. For me, it’s about a long lost little girl who is no longer ________. Now I know that ________ and receiving are two halves of a whole, each incomplete without the other.

On February 16, 1861, a big earthquake struck Sumatra, an Indonesian island. The earthquake shook the     1    (west)side of the island, causing a tsunami (海啸). That wall of water crashed into the shore,     2     (destroy) towns and taking thousands of     3    (life).

Recently, though, a team of scientists discovered that another earthquake occurred before this deadly event. According to the record, that earthquake     4    (start) in 1829 and lasted for 32 years but no one felt even one shake. This kind of slow-moving earthquake     5    (call) “silent earthquakes” because no instrument can find them. Scientists have only begun discovering them because    6     the advances in GPS technology in the last twenty years.

To figure out what is going on under the ground, scientists need to study earthquakes. Every earthquake, either small     7     big, can teach scientists something about how much the ground will shake in the future. Unluckily, no one can predict (预测) when an earthquake will hit. Scientists just have to prepare to study all earthquakes     8     strike.

But silent earthquakes like the one in Sumatra change the game for scientists. These silent earthquakes happen all over     9    world. Sometimes, a silent earthquake happens just before a regular one, both of which might be related. By studying silent earthquakes, scientists hope to     10     (well) understand regular earthquakes than before and possibly predict them.

9 . Last Thursday, Michael and Linda were distributing (分发) meals to 4,000 homeless people for their wedding reception (婚宴) in the border town of Kills. The _________ had decided that instead of playing host to their friends and family with a traditional feast reception, they _________ to feed the homeless people from an earthquake-stricken area.

The idea came from Michael’s father, Ted, who _________ for a Turkish relief organization. For the past few years, the organization has handed out _________ meals to thousands of people who’ve suffered from natural disasters. He called Adam, who was _________ the organization, and suggested that the family cover part of the cost of feeding them for the day.

Then he told his son, who was surprised by the _________, but soon agreed. When he told that to Linda, she was really shocked but finally _________ because in southeastern Turkey there is a real culture of sharing with people _________. They love to share their _________, their table and everything they have. And afterwards she was quite __________ in it. So, they arrived at the __________ on Thursday to spend the day serving food and taking photographs with their grateful recipients (接受者).

On Tuesday evening, the __________ married couple were still pleased with their decision to __________ a personal celebration for one with greater good. Michael said, “A small act of __________ could make a big difference. __________, this will give the start for other wedding dinners to be held here with our brothers and sisters in need.”

Cheering, dancing and singing, local people and tourists gathered around the fire during the Torch Festival of the Yi People in Bijie, Guizhou, on Aug 12. The festival     1     (list) as a national intangible cultural heritage(非物质文化遗产) in 2011.

There are different stories about how the festival started. But     2     (probable) it was because of the natural worship(崇拜) of fire by the Yi people. Fire was important since their ancestors could use it to bring light as well as     3     (warm) and cook food. One Yi ethnic proverb says, “Everything you eat must’see’ fire.” This is due to     4     old practice. Before bringing meat into the home from the outside, a small fire must first be lit outside and the meat should be smoked on the fire. In farming, fire was used     5     (light) piles of branches and leaves,     6     were later buried in the ground.

The Yi people used to celebrate the harvest, as a way to pray for a good harvest and drive away evil from their homes and farmland. Today it has become a     7     (society) event where people come together to light torches and join in various     8     (activity) such as building bonfires, horse racing, wrestling, bullfighting and beauty contests. The festival also provides people     9     a chance to expand their circle of friends. Through the festival, the Yi people not only share their joy and thanks for their good life,     10     get more people to understand their lifestyle and traditions.