The World Health Organization (WHO) has announced a shocking finding about the air we breathe. It has found that almost everyone on Earth breathes unhealthy air. The WHO made     1    (it) air quality update ahead of World Health Day on April 7. The update reported that 99 per cent of the world’s population breathes air     2     goes beyond WHO air quality limits. It looked at data from over 6,000 cities in 117 countries. People     3    (live) in lower- and middle-income countries breathe the poorest-quality air. Millions of people die in these countries because of pollution-related diseases. The WHO said: “After surviving a pandemic, it is unacceptable to still have 7 million preventable deaths due     4     air pollution.”

The WHO said its report highlighted the need to move away from fossil fuels. It asked governments to do more     5     (reduce) levels of air pollution. It said: “Current energy concerns highlight the importance of speeding up the transition to cleaner and     6    (healthy) energy systems.” It added that high gas prices, energy     7    (secure), the dangers of air pollution, and climate change mean the world must be less dependent on fossil fuels. The WHO report     8    (include) many recommendations for change. One of these is     9     use of clean energy for cooking, heating and lighting. Another is to “build safe and affordable public transport systems and pedestrian- and cycle-friendly     10    (network)”.

2 . If having to make a choice between reading an e-book and a printed book, which would most people choose? Some would go for an e-book while some still prefer the hard-printed book.

Undoubtedly, e-books do have benefits. Firstly, changes to an electronic publication are relatively easy to make. They are quicker to obtain. E-books are more easily updated. The printed books on many subjects can become outdated very quickly. Secondly, e-books can be easily and quickly kept up to date. You usually get far more than just the e-books. Most e-books are sold with bonuses and related information that usually do not come with the purchase of a printed book. Moreover, they take up less space. Instead of a big library, you can fit literally thousands of books on your computer. It also makes it easier to share this information with families and friends.

For nearly twenty years, additionally, futurists have been predicting the development of printed books. The conventional view has been that digital e-books are on the verge of replacing paper books. However, this has not been the case. A printed book has its advantages too. Firstly, it is an object that can be carried and used alone. It needs no electric outlet (插座), no batteries, nothing. Secondly, e-books will always require some forms of support that the printed book does not need.

I believe that the online publishing has not taken off because people want real books. What is being published online more and more are pamphlets (小册子) and things that really do not need to be in print. These are stuff that people throw away afterward. More often, people do not want to read a book on the computer. What could be better than a paper book? It lasts a long time. These books are designed to last a long time without disappearing.

To sum up, there is no denying that the printed book is still very much preferred over its digital cousins. Reading electronic publications is just not the same when it comes to books. People are still very interested in real books and notebooks.

3 . Studies on the importance of sleep for health and the various effects of not having enough sleep have long been well-known. Being short of sleep can lead to poor memory and daytime sleepiness. It’s also been connected to diseases and weakens immune(免疫的)function. However, more than three-quarters of us fall asleep after 11pm and nearly a third stay up until 1am.

The concept(概念)of sleep procrastination was introduced in a 2014 study by Utrecht University in The Netherlands, which explained that it meant “failing to go to bed at the intended time, while nothing prevents a person from doing so”. If so, it will bring terrible results.

Studies have shown that “bedtime procrastination” is connected with a person’s working life during the day. “They feel out of control in their day life and the night is when they can be free,” says Dr Saliha Afridi. “It is full of things they ‘have to do’ rather than what they ‘want to do’. ” Studies have also found that increased working hours and the reduced leisure time may cause much stress and sleep procrastination. On occasion, people have trouble with feelings, concern and loneliness, so they were controlled by using social media, making them stay up late.

So how to avoid it? People should avoid thinking too much before bedtime and stay away from digital devices. Besides, taking a warm shower before bed and going to bed at the intended time are also important.

4 . If you're a runner who secretly hates running, here's some good news: settling into a leisurely jog rather than an all-out run may actually be better for your health in the long term.

A team from Denmark followed over 5,000 people taking part in the Copenhagen City Heart Study, and tracked whether they were non-joggers or joggers who kept a slow, moderate, or fast pace. The participants' health was tracked over the next 12 years, and so was their mortality (死亡率): 28 of the joggers and 128 of the non-joggers died.

The connection was this: Joggers of mild and moderate intensity had a lower risk of death than the fast joggers. In fact, the lowest mortality risk was that of the mild intensity joggers. The fast-paced joggers had about the same mortality rate as sedentary (久坐的) people. This suggests that there may be an upper limit to hard exercise, after which the benefits fall off.

"The U-shaped association between jogging and mortality suggests there may be an upper limit for exercise amount that is best for health benefits," said study author Peter Schnohr. "Anything more is not just unnecessary: it may be harmful." From the current study, jogging just three times per week, for less than 2.5 hours/week was associated with the lowest overall mortality risk.

There've been a lot of mixed messages about the "right" amount of exercise and what intensity is best. The World Health Organization has suggested that the current 150 minutes/week recommendations are strenuous for most people to tackle, and that expectations should be lowered, since, after all, anything is better than nothing. Everyone probably has a level of activity that feels best to him or her. But at least the growing consensus seems to be that more-if you're pushing yourself very hard-is not necessarily better. And it may even be worse.