What was the fiercest(最凶猛的) animal in history? The answer is the Tyrannosaurus rex(霸王龙). This dinosaur lived in North America over 65 million years ago. It had a giant body, big head, sharp teeth and strong legs. All of (A)these made this animal the most powerful hunter in nature. But look at its arms. They were so small and short. It seemed that they must be useless.

But in fact, their arms could do a lot more than we think.

According to scientists from Stockton University of the US, the dinosaur could turn the palms of its hands toward its chest. This might help the animal hold food close to its mouth for eating, Matthew Bonnan from the university told Live Science.

Also, its small arms and large claws could be useful too. They could help to (B)tear into its food. Their arms were short, so they could move quickly. Scientists think the dinosaur could seriously wound his prey in just a few seconds.

Rice is one of the most commonly eaten basic foods around the world. Buying it and cooking it is a daily matter. Yet for many, its presence has been a matter of life and death. It is a main food because it is easy to grow, besides low cost and convenience. A poor community in the developing world may find it difficult to bring in foreign fruits or raise cattle for meat, but it can almost certainly use the land it has in order to grow plenty of rice.

This was the great achievement of Yuan Longping, who passed away on May 22 this year. A great Chinese scientist, Yuan successfully developed what is known as “hybrid rice” which can produce up a 30% higher output. Yuan Longping was born in the year 1930, a time when China was very different. It was a nation, without modern industry, depending on the rice which they grew. The first few decades (十年) of his life were met with major social events, and a rapidly growing population that made food supply not last all the time. This experience left its mark on Yuan Longping, which made him focus on (关注) farming science and work on his research of hybrid rice.

His achievement would see the rice supply in China increasing from 56.9 million tons in 1950 to 194.7 million tons by 2017. By 1991, 20% of the world’s rice output came from hybrid rice, even if only being planted in 10% of fields.

Always remember, human development begins first with the most basic and sample things, such as developing rice. We should be thankful for scientific thinkers like Yuan.

Have you ever counted the number of digits (数字) in your mobile phone number? Your number has 11 digits. You may sometimes find it hard to remember your number. That’s because China has the longest mobile phone numbers in the world. Why is that?

The 11 digits can be divided into three parts. Each pare has a different meaning. The first three numbers tell you which mobile phone service provider you are using. For example,135 is for the China Mobile Communications Corporation ( 中 国 移 动 ) and 188 is for China Unicom ( 中 国 联 通 ). The fourth to the seventh digits tell you which region the number is registered (注册) in. And the last four digits are random (随机的).

The main reason for using 11 digits is that we have the largest population in the world. We once had 10 numbers. But as our population grew, there were not enough numbers for us to use. So we began to use 11 digits starting from 1999.

Eleven digits can be used to make tens of billions of mobile phone numbers, according to the Xinhua News Agency. That’s enough for each person to have seven or eight phone numbers to use in China.

Plus, mobile phone numbers can be recycled. Usually, the service provider will reuse a canceled number after three to six months. If you call a number that you haven’t contacted for a long time, you may find that its owner has changed.

Besides China, Britain and Japan also use 11-digit   mobile phone numbers. But their numbers always start with 0. So they cannot create as many numbers as we can. Countries like   the United   States,   Australia   and India   use phone numbers   with 10 digits.   Canada’s mobile phone numbers are perhaps the world’s shortest: they use seven digits.