I serve as an educator and health care provider as well, therefore, I have worked with numerous children infected with the virus that causes AIDS. The relationships that I have had with these special kids have been gifts in my life. They have taught me so many things, but I have especially learned that great courage can be found in the smallest of packages. Let me tell you about Tyler.

    Tyler was born infected with HIV: his mother was also infected.From the very beginning of his life, he was dependent on medications to enable him to survive.When he was five, he had a tube surgically inserted in a vein in his chest.This tube was connected to a pump, which he carried in a small backpack on his back. Medications were hooked up to this pump and were continuously supplied through this tube to his bloodstream.At times, he also needed supplemented oxygen to support his breathing.

    Tyler wasn't willing to give up one single moment of his childhood to this deadly disease.It was not unusual to find him playing and racing around his backyard, wearing his medicine-laden backpack and dragging his tank of oxygen behind him in his little wagon.All of us who knew Tyler marveled at his pure joy in being alive and the energy it gave him.Tyler's mom often teased him by telling him that he moved so fast that she needed to dress him in red.That way, when she peered through the window to check on him playing in the yard, she could quickly spot him.

    This dreaded disease eventually wore down even the likes of a little dynamo (精力充沛的人) like Tyler. He grew quite ill and, unfortunately, so did his HIV-infected mother.When it became apparent that he wasn't going to survive, Tyler's mom talked to him about death.She comforted him by telling Tyler that she was dying too, and that she would be with him soon in heaven.

    A few days before his death, Tyler beckoned me over to his hospital bed and whispered, “I might die soon.I'm not scared.When I die, please dress me in red.Mom promised she's coming to heaven, too.I'll be playing when she gets there, and I want to make sure she can find me.”

    One day an old woman was travelling alone in the mountains. Suddenly she saw something shining in the stream（溪流）. When she came close, she found it was a precious（宝贵的）stone. She put the stone into her bag and went on with her trip.

    The next day the old woman met a young man, who was also a traveler in the mountains. The young man looked very hungry, so the old woman opened her bag to share her food. The hungry traveler saw the precious stone and asked carefully, "The stone is beautiful. Would you like to give it to me?"

    "Sure. Why not?" the woman said, and handed the stone to him.

    The young man left happily with the stone. He knew it was worth enough to give him security for a lifetime. But a few days later he came back to return the stone to the woman.

    "I've been thinking." he said. "I know how valuable the stone is, but I give it back and hope that you can give me something even more precious. Give me what you have in your bag."

    The woman opened her bag. It was almost empty. She looked at the young man and smiled, "I have nothing special in my bag, but I do have something precious—the joy of giving!"

    The young man felt ashamed (惭愧的）and left silently.

    The popular wisdom for years has been that drinking in moderation (适度)—that's one “standard” drink a day for women and two for men-is linked to a lower risk of cardiovascular (心血管的) disease. But recent studies are casting some doubt on that long-held learning. Science now says it depends on your age and drinking habits.

    A 2017 study of nearly 2 million British with no cardiovascular risk found that there was still a modest benefit in moderate drinking, especially for women over 55 who drank five drinks a week. Why that age? Alcohol can influence the substance in the blood in positive ways, experts say, and that's about the age when heart problems begin to occur.

    Also, a 2018 study found that drinking more than 100 grams of alcohol per week—equal to roughly seven standard drinks in the United States or five to six glasses of wine in the UK—increases your risk of death from all causes and in turn lowers your life expectancy. Links were found with different forms of cardiovascular disease, with people who drank more than 100 grams per week having a higher risk of stroke, heart failure.

    Another 2018 study found that consistently drinking a moderate amount of alcohol, within recommended guidelines, had a protective effect on the heart over time. Unstable drinking habits were associated with a higher risk of heart disease, which the authors reflected might indicate broader lifestyle changes, such as poor health or stress. Former drinkers were also at greater risk.

    Overall, however, the latest thinking is that any heart benefit may be outweighed by other health risks, such as high blood pressure, certain cancers and liver damage.

Women who drink are at a higher risk for breast cancer; alcohol contributes about 6% of the overall risk, possibly because it raises certain dangerous hormones in the blood. Drinking can also increase the chance you might develop liver, mouth and oral cancers. One potential reason: Alcohol weakens our immune systems, making us more likely to inflame (发炎)—a driving force behind cancer.

    It's difficult to know the exact answer to whether babies dream and what they dream about. However, sleep experts have shown that newborns dream the most in the first two weeks after birth. Babies spend most of their sleeping time in REM(rapid eye movement) stage. As dreaming takes place in a light state of sleep, newborns tend to wake up due to noises, movements and other factors. When dreaming, newborns make a few noises and their eyes move. They may move around the sides or up and down. They may laugh, scream, or cry during the REM sleep. Also, their facial muscles, hands, and legs move, due to which they may wake up. So wrapping a baby in swaddling(裹紧的) clothes can keep the baby's body from moving and help them sleep better. As babies grow, their body movement decreases when dreaming.

    Studies say that the brain activity associated with dreaming is essential for the babies' mental development. During the REM stage, the flow of blood to the brain increases. As a result, certain nerve proteins are produced, which are the building units of the brain. Babies get stimulation from what they see, hear, or feel. The brain processes the information acquired while awake, and stores what is essential to the individual. A study concludes that babies learned while they were dreaming.

    What's the time for babies to start dreaming? Researchers say that before birth, babies start experiencing REM sleep around week 25, and so they may start dreaming at the point. On the contrary, some psychologists believe that children start having dreams when they are about 5 years old. At that age, they start becoming aware of themselves and begin to understand the things around them, which is what dreams are actually made of.

    On Sunday, November 3, 2019, most North Americans will mark the end of Daylight Saving Time (DST) by moving their clocks back an hour. This simple action will not only add an extra 60 minutes to their weekend, but also shift (变换，变动) daylight back into the morning hours, making it a little less painful to wake up for school and work during the shorter winter days.

    Operating the clocks was first suggested by Benjamin Franklin in 1784. He mentioned the idea in a letter to the editor of the Journal of Paris and advised it should be a way to save candles, but it was not taken seriously. George Hudson from New Zealand also recommended moving the clocks back two hours in 1895 to get extra daylight time to study insects. Unfortunately, neither he nor British people William Willett, who suggested it in 1907 as a way to save electricity costs, got their wish.

    It was the German Empire that began the clock shifting tradition on April 30, 1916, to save fuel needed to produce weapons and bombs for World War I. Though a few others, including the US and Britain, adopted the tradition shortly after, all the countries returned to Standard Time once the war ended, only to start DST again during World War II. Once the battle ended in 1945, the US government ended DST nationally but allowed states and districts to continue the tradition and even allowed them to establish their own start and stop dates.

    However, though there have been many attempts to persuade lawmakers to end DST, both in the US and Europe, they have not been successful. Therefore, unless you live in places like Hawaii and Arizona, you have little choice but to "Fall Back" and enjoy the extra hour this weekend! Health experts suggest the best way to adjust is going to bed at your regular time, even if the day is an hour longer.

As a young girl growing up in France, Sarah Toumi dreamed of becoming a leader who could make the world a better place. Her passion to help others was awakened when, from the age of nine, she accompanied her Tunisian father to his birthplace in the east of the country during holidays. There she organized homework clubs and activities for children. Toumi witnessed first-hand the destructive effect of desertification. "Within 10 years rich farmers became worse off, and in 10 years from now they will be poor. I wanted to stop the Sahara Desert in its tracks." A decrease in average rainfall and an increase in the severity of droughts ( 干 旱 ) have led to an estimated 75 percent of Tunisia's agricultural lands being threatened by desertification. 

Toumi recognized that farming practices needed to change. She is confident that small land areas can bring large returns if farmers are able to adapt by planting sustainable crops, using new technologies for water treatment and focusing on natural products and fertilizers (肥料) rather than chemicals. 

In 2012, Toumi consolidated her dream to fight the desert. She moved to Tunisia, and set up a programme named Acacias for All to put her sustainable farming philosophy into action. "I want to show young people in rural areas that they can create opportunities where they are. Nobody is better able to understand the impact of desertification and climate change than somebody who is living with no access to water." 

By September 2016, more than 130, 000 acacia trees had been planted on 20 pilot farms, with farmers recording a 60 percent survival rate. Toumi estimates that some 3 million acacia trees are needed to protect Tunisia's farmland. She expects to plant 1 million trees by 2018. In the next couple of years, Toumi hopes to extend the programme to Algeria and Morocco.