South Africa is a multiethnic society encompassing a wide variety of cultures, languages, and religions. It has 11 official languages. If you want to say hello, it's "sawubona" in Zulu, and "hallo" in Afrikaans. Now, South Africa's school children may start using "ni hao" to say hello.

    The country's education minister says, the nation is adding the Mandarin language teaching in some schools. Mandarin is the official spoken language of China. That country is a major trading power for South Africa.

    A recent agreement between the two nations centers on five areas of cooperation. They include development in basic education, school books and lessons, mathematics and science, teacher training and career education and research.

    South Africa officials have not said how much they teaching Mandarin will cost. Troy Martens is an officials with South Africa's Ministry of Basic Education. She says the new partnership is extremely valuable.

    A public opinion study last year found that South Africans have mixed feelings about China. The survey showed 46 percent of South Africans do not like the spread of Chinese ideas and customs in their country, the results also showed that 60 percent dislike Chinese music, movies and television.

    But Ms Martens said Chinese trade is more important than those feelings. She said it is extremely helpful to learners in South Africa to study Mandarin as well as Chinese culture. And she said not every school will offer Mandarin.

    “Now this will not be compulsory, it will not be for every school, and it will not be for every child. But for schools that feel they have the capacity to offer Mandarin as a subject, we think it is a great opportunity for South African learners to be exposed to this international type of language,” said Martens.

    Lisette Noonan heads the 80-year-old Pretoria Chinese School in South Africa's capital. The school serves about 500 students from kindergarten to grade 12. Every student studies Mandarin.

    Ms Noonan says the school welcomes the new cooperation between South Africa and China. She said it is in the best interests of children to study Mandarin. She said that especially true with China becoming what she called “a huge economic power in the world”

    As self-driving cars come closer to being common on American roads, much of the rhetoric（说辞）promoting them has to do with safety. About 40,000 people die on U.S. roads every year, and driver errors are linked to more than 90 percent of crashes. But many of the biggest advocates of autonomous（自动的）vehicles aren't car companies looking to improve the safety of their existing products. Huge support for itself-driving technologies is coming from Silicon Valley giants like Google and Apple.

    Those of us who have studied the relationship between technology and society tend to look more carefully at the motivations behind any technologically push. In this case, it's clear that in addition to addressing safety concerns, Silicon Valley firms have a strong incentive（动机）to create a new venue for increasing the use of their digital devices. Every minute people spend on their mobile phones provides data—and often money—to tech companies.

    At present, digital devices and driving are in conflict: There are serious, often fatal, consequences when drivers use smartphones to talk or to text. Regulators and safety advocates look to resolve dial conflict by banning phone use while driving – as has happened in almost every state. But the tech companies are taking a different approach. The obvious answer for Silicon Valley is creating an automobile in which continuous cellphone use no longer poses a threat to anyone.

    In recent years, the amount of time adults spend on their mobile devices has grown rapidly. At the moment, it's around four hours a day for the average adult in the U.S. However, that rapid growth is likely to slow down as people run out of time that's available for them up to use their devices. Unless, of course, there's a new block of time that suddenly opens up. The average American now spends about 48 minutes in a car every day, a sizeable opportunity for increased cellphone use.

    Sop as the public conversation around autonomous cars highlights the safety advantages, don't forget the tech industry's powerful desire for more profits, which goes well beyond simply saving us from ourselves.

    The park bench was deserted as I sat down to read beneath the branches of an old willow tree, with good reason to frown, for the world was dragging me down. At this time, a boy approached me. He stood right before me, and said with great excitement, "Look what I found!"

    In his hand was a flower, and what a pitiful sight, with its petals (花瓣) all worn. Wanting him to take his flower and go off to play, I managed a smile and then turned to the other side.

    But instead of leaving, he sat next to my side and placed the flower to his nose and declared, "It really smells pretty and it's beautiful, too. That's why I picked it. Here it's for you."

    The flower before me was dying or dead. But I knew I must take it, or he might never leave. So I reached for the flower, and replied, "Just what I need."

    But instead of placing the flower in my hand, he held it in mid-air. It was then that I noticed that the boy was blind.

    I heard my voice quiver (轻微颤抖), and at the same time my tears shone like the sun. As I thanked him for picking the very best one, he smiled and said, "You're welcome." And then he ran off to play, unaware of the impact he'd had on me.

    I sat there and wondered how he managed to see a self-pitying woman beneath an old willow tree. Perhaps from his heart, he'd been blessed with true sight.

    Through the eyes of the blind boy, I could see the problem was not with the world; the problem was me. And for all of those times I had been blind. From now on, I promised to see beauty and appreciate every second. Then I held the flower up to my nose and breathed its fragrance and smiled as that young boy.

    In our twenties, we find it funny when we can't remember our neighbor's cat's name or a handsome actor who starred in a famous movie. In our thirties, we jokingly call it "brain freeze". In our forties, we laugh it off as a" senior moment" and follow up with one of these old age jokes. But the reality is that there comes a point when being forgetful stops being funny and starts to seem a bit dreadful. You think, "Am I losing it？"Or worse, "Is this a sign of Alzheimer's disease（老年痴呆症）？"

    Well, don't worry. The fact that you recognize your own forgetfulness may be a very good sign, at least in terms of the possibility of your developing Alzheimer's disease（AD）. The researchers in a new study show that it's not forgetfulness but not being aware that we're forgetful that we should fear.

    The researchers began with the assumption that one common feature of Alzheimer's dis-ease is a damaged awareness of illness. And they wanted to prove their theory that the lack of awareness can be used to predict whether someone with" mild cognitive（认知的）damage" will progress to full-on AD. For the study, "mild cognitive damage" was defined as someone whose mental state was considered healthy but who had either complained of memory loss or had suffered objective memory loss.

    The researchers used existing data for 1, 062 people between the ages of 55 and 90 that had been recorded over a 12-year period. The data included brain scans, which the researchers used to look for visual signs of reduced glucose uptake（葡萄糖吸收）.It is an objective marker of the sort of reduced brain function that goes along with AD.As expected, glucose uptake was reduced in those with AD. What the researchers also discovered was that glucose uptake was reduced in those with mild cognitive damage who also showed evidence of reduced illness awareness. Finally, the researchers found that those who had reduced illness awareness were more likely to develop AD than those without.

    Please take a few seconds and think of your personal biggest goal. Imagine telling someone you meet today what you're going to do. Imagine their congratulations and their high image of you. Doesn't it feel good to say it out loud? Don't you feel one step closer already? Well, bad news: you should have kept your mouth shut, because that good feeling will make you less likely to do it.

    Any time you have a goal, there is some work that needs to be done to achieve it. Ideally, you would not be satisfied until you'd actually done the work. But when you tell someone your goal and he acknowledges (认可) it, psychologists have found it's called a "social reality". The mind is kind of tricked into feeling that it's already done. And then, because you've felt that satisfaction, you're less motivated to do the actual hard work necessary. This goes against the traditional wisdom that we should tell our friends our goals, right?

    In 1982, Peter Gollwitzer, a Professor of Psychology, wrote a whole book about this. And in 2009, he did some new tests that were published. It goes like this: 163 people across four separate tests—everyone wrote down their personal goal. Then half of them announced their commitment (许诺) to this goal to the room, and half didn't. Then everyone was given 45 minutes of work that would directly lead them towards their goal, but they were told that they could stop at any time. Now those who kept their mouths shut worked the entire 45 minutes on average, and when asked afterwards, said they felt they had a long way to go to achieve their goal. But those who had announced it quit after only 33 minutes on average, and when asked afterwards, said that they felt much closer to achieving their goal.

A new study says that more than half the world's ocean area is "becoming greener," and the trend is connected to human-caused global warming.

It's not clear what is driving the greening. In some places, it could indicate changes in the amount of plankton or other organic material floating in the water. Plankton are a cornerstone of the ocean food chain, and these kinds of shifts could have ripple effects throughout the entire marine ecosystem.

The study, published on Wednesday in the journal Nature, examines 20 years of satellite data measuring light reflected at the surface of the water all across the globe, subtle changes that aren't necessarily visible to the naked eye. The research finds that 56 percent of the world's oceans are shifting in color — and on the whole, they're growing greener. The trend is especially strong in the lower latitudes, including the subtropics and tropics.

The researchers then used a computer model to find out whether climate change was playing a part. They conducted one set of simulations representing the oceans under a strong climate change scenario, and then compared them with a second set of simulations imagining a world in which climate change didn't exist. The model suggests that rising global temperatures are to blame.

The exact reasons still require some scientific digging. While climate change seems to be the culprit, the study also indicates that rising ocean temperatures in and of themselves aren't driving the greening.

There are plenty of other ways global warming is affecting the world's oceans, by changing the structure and flow of certain currents, for instance. These kinds of changes can affect the growth of phytoplankton and other factors that might be contributing to the greening.

The findings weren't a surprise to the researchers. They're consistent with the way researchers expect the global oceans to change as the world keeps on warming.

"I've been running simulations that have been telling me for years that these changes in ocean color are going to happen," study co-author Stephanie Dutkiewicz, a senior research scientist at the Massachusetts Institute of Technology, said in a statement. "To actually see it happening for real is no unexpected, but frightening."