Tibetan antelopes live on the plains of Tibet     1     the air is thin. Watching them move slowly across the green grass, I     2    (strike) by their beauty. But the 1980s and 1990s were bad time for the Tibetan antelopes when they were     3    (illegal) hunted for their valuable fur. Their habitats became smaller because new roads and railways     4    (build). As a result, the population of the Tibetan antelopes dropped by more than 50 percent. In order to prevent this species from     5    (extinct), the Chinese government took     6    (effect) measures to place it under national     7    (protect). Luckily, the antelope population has recovered. However, the government does not intend     8    (stop) the protection, since the     9    (threat) to the Tibetan antelope have not yet disappeared. Only when we learn to exist in harmony     10     nature can we stop being a threat to wildlife and to our planet.

It's known to all that human beings are social animals. We spend a lot of our     1    (wake) hours communicating with others, and the possibilities of conversation are seemingly     2    (end)—we can make plans and jokes, talk about the past, dream about the future, share ideas and spread information. This ability to communicate has played     3     part in our species' ability to not only survive, but also develop.

Do you choose how     4    (use) this powerful tool—communication? Do your conversations serve as doorways to new ideas and experiences? Or do you     5    (usual) just like to talk about yourself? If you're like most people, your own thoughts and experiences may be your favorite topics of conversation.     6     average, people spend 60 percent of conversations talking about themselves—and this figure     7    (jump) to 80 percent when they are communicating via social media plat forms.

Why, in a world full of ideas to discover, develop, and discuss, do people spend the majority of their time talking about themselves? Recent research suggests a simple     8    (explain): because it feels good. Self-reveal produces a burst of activity in neural region     9    (associate) with pleasure, motivation and reward. But feeling good may be no more than a means to an end—it may be the immediate reward     10     starts a cycle of self-sharing, finally leading to wide varieties of long-term benefits.

Many millions of years later, the first     1     (extreme) small plants began to appear on the surface of the water. They multiplied and filled the oceans and seas     2     oxygen,     3     encouraged the later development of early shellfish and all sorts of fish. Next, green plants began to grow on land. They     4     (follow) in time by land animals. Some were insects.     5    , called amphibians, were able to live on land as well as     6    the water. Later when the plants grew into forests, reptiles appeared for the first time. They produced young generally by laying eggs. After that, some huge animals, called dinosaurs, developed. They     7     (lay) eggs too and existed on the earth for more than 140 million years.     8    , 65million years ago the age of the dinosaurs ended. Why they suddenly disappeared still remains a mystery. This     9     (appear) made possible the rise of mammals on the earth. These animals were different from all life forms in the past,     10     they gave birth to young baby animals and produced milk to feed them.

Lonely and single middle-aged men are at an increased risk of developing cancer than those in a relationship with people around them, according to a new study.

A team from the University of Eastern Finland worked with 2,570 middle-aged men, monitoring their     1     (healthy)and mortality (死亡率)from     2     1980s to the present day. Over the course of the study 25% of participants had developed cancer, with 11% of the Finnish men involved     3     (die)from the condition.

There was a ‘clear link’ between loneliness and an increased risk of cancer, the team explained, with being lonely increasing the risk of cancer     4     about ten percent.     5     (global), cancer is the second leading cause of death. Loneliness has been suggested as a risk factor for cancer mortality. However, connections between loneliness, social isolation and cancer     6     (understand)poorly.

Recent     7     (study) have suggested that loneliness could be as significant a health risk as smoking or being overweight, according to the researchers. Their findings support the idea     8     attention should be paid to this issue. In addition, cancer mortality was much     9     (high) in cancer patients who were unmarried, widowed or divorced.

Awareness of the health effects of loneliness is constantly increasing. Therefore, it is important to examine, in more detail, the mechanisms (机制) by     10     loneliness causes harmful health effects.