1 . Human speech contains more than 2,000 different sounds, from the common “m” and “a” to the rare clicks of some southern African languages. But why are certain sounds more common than others? A ground-breaking, five-year study shows that diet-related changes in human bite led to new speech sounds that are now found in half the world’s languages.

More than 30 years ago, the scholar Charles Hockett noted that speech sounds called labiodentals, such as “f” and “v”, were more common in the languages of societies that ate softer foods. Now a team of researchers led by Damián Blasi at the University of Zurich, Switzerland, has found how and why this trend arose.

They discovered that the upper and lower front teeth of ancient human adults were aligned (对齐), making it hard to produce labiodentals, which are formed by touching the lower lip to the upper teeth. Later, our jaws changed to an overbite structure (结构), making it easier to produce such sounds.

The team showed that this change in bite was connected with the development of agriculture in the Neolithic period. Food became easier to chew at this point. The jawbone didn’t have to do as much work and so didn’t grow to be so large.

Analyses of a language database also confirmed that there was a global change in the sound of world languages after the Neolithic age, with the use of “f” and “v” increasing remarkably during the last few thousand years. These sounds are still not found in the languages of many hunter-gatherer people today.

This research overturns the popular view that all human speech sounds were present when human beings evolved around 300,000 years ago. “The set of speech sounds we use has not necessarily remained stable since the appearance of human beings, but rather the huge variety of speech sounds that we find today is the product of a complex interplay of things like biological change and cultural evolution,” said Steven Moran, a member of the research team.

May 21st this year marks the first International Tea Day, which was named officially     1     the United Nations on November 27th, 2019. To celebrate     2     festival, a number of events took place at the Chinese Businessman Museum in Beijing on Thursday.

The chairman of the China Culture Promotion Society     3     (address) the opening ceremony. “As a main promoter of the International Tea Day, the birthplace of tea and the     4     (large) tea-producing country, China has a     5     (responsible)to work with other countries to promote the healthy development of the tea industry. It can help to build a community with a     6     (share) future for mankind,” he said.

The “First International Tea Day Tea Road Cooperative Initiative” issued (发布) at the ceremony calls for people working in the tea industry to come together to promote international cooperation     7     cultural exchanges. A four-year tea promotion —Tea Road Cooperative Plan — was also issued in accordance with the initiative.

    8     (strengthen)the connection with young people, the event included a number of public promotional activities on social media,     9     (invite) twenty-nine tea professionals from around the world to have thirty-six hours of uninterrupted live broadcasts.

The Chinese Ancient Tea Museum was officially unveiled (揭幕) at the ceremony, opening     10     (it)first exhibition: The Avenue of Truth — A Special Exhibition of Pu’er Tea.

4 . Can a small group of drones (无人机) guarantee the safety and reliability of railways and, at the same time, help railway operators save billions of euros each year? That is the very likely future of applying today’s “eyes in the sky” technology to make sure that the millions of kilometres of rail tracks and infrastructure (基础设施) worldwide are safe for trains on a 24/7 basis.

Drones are already being used to examine high-tension electrical lines. They could do precisely the same thing to inspect railway lines and other vital aspects of rail infrastructure such as the correct position of railway tracks and switching points. The more regularly they can be inspected, the more railway safety, reliability and on-time performance will be improved. Costs would be cut and operations would be more efficient (高效) across the board.

That includes huge savings in maintenance costs and better protection of railway personnel safety. It is calculated that European railways alone spend approximately 20 billion euros a year on maintenance, including sending maintenance staff, often at night, to inspect and repair the rail infrastructure. That can be dangerous work that could be avoided with drones assisting the crews’ efforts.

By using the latest technologies, drones could also start providing higher-value services for railways, detecting faults in the rail or switches, before they can cause any safety problems. To perform these tasks, drones for rail don’t need to be flying overhead. Engineers are now working on a new concept: the rail drones of the future. They will be moving on the track ahead of the train, and programmed to run autonomously. Very small drones with advanced sensors and AI and travelling ahead of the train could guide it like a co-pilot. With their ability to see ahead, they could signal any problem, so that fast-moving trains would be able to react in time.

5 . Henry Raeburn (1756-1823)

This exhibition of some sixty masterpieces celebrating the life and work of Scotland’s best loved painter, Sir Henry Raeburn, comes to London. Selected from collections throughout the world, it is the first major exhibition of his work to be held in over forty years.

Scottish National Portrait (肖像画) Gallery presents a series of lectures for the general public. They are held in the Lecture Room. Admission to lectures is free.

Monday-Saturday 10.00-17.45             Sunday 12.00-17.45

Last admission to the exhibition: 17.15. There is no re-admission.

Closed: 24-26 December and 1 January.

£4. Children under 12 years accompanied by an adult are admitted free.

A special low entrance charge of £2 per person is available to all in full-time education, up to and including those at first degree level, in organised groups with teachers.

7 . Sometime in the early 1960s, a significant thing happened in Sydney, Australia. The city discovered its harbor. Then, one after another, Sydney discovered lots of things that were just sort of there — broad parks, superb beaches, and a culturally diverse population. But it is the harbor that makes the city.

Andrew Reynolds, a cheerful fellow in his early 30s, pilots Sydney ferryboats for a living. I spent the whole morning shuttling back and forth across the harbor. After our third run Andrew shut down the engine, and we went our separate ways — he for a lunch break, I to explore the city.

“I’ll miss these old boats,” he said as we parted.

“How do you mean?” I asked.

“Oh, they’re replacing them with catamarans. Catamarans are faster, but they’re not so elegant, and they’re not fun to pilot. But that’s progress, I guess.”

Everywhere in Sydney these days, change and progress are the watchwords (口号), and traditions are increasingly rare. Shirley Fitzgerald, the city’s official historian, told me that in its rush to modernity in the 1970s, Sydney swept aside much of its past, including many of its finest buildings. “Sydney is confused about itself,” she said. “We can’t seem to make up our minds whether we want a modern city or a traditional one. It’s a conflict that we aren’t getting any better at resolving (解决).”

On the other hand, being young and old at the same time has its attractions. I considered this when I met a thoughtful young businessman named Anthony. “Many people say that we lack culture in this country,” he told me. “What people forget is that the Italians, when they came to Australia, brought 2000 years of their culture, the Greeks some 3000 years, and the Chinese more still. We’ve got a foundation built on ancient cultures but with a drive and dynamism of a young country. It’s a pretty hard combination to beat.”

He is right, but I can’t help wishing they would keep those old ferries.