All over the world the need for more laptops and computers increases each year. Networks have been part of our life. Probably everyone with a portable device （移动设备）has once logged on to a public WiFi network without paying for it, while they are having a coffee, on a train, in a shopping mall or at a hotel. However, is this kind of public WiFi network safe?

    Some networks are better protected than others because encryption （加密）methods are used. Therefore, they are safer than others. But a survey in 2015 showed that more than 950 million records were not protected, including addresses, emails, birth dates, phone numbers, passwords and so on. These open WiFi networks are really not safe, because it is very easy for hackers （黑客） to break into the operating system and get people's private information.

    Most smartphones and laptops, by themselves, search and connect to WiFi networks. They usually prefer a network with a connection that has been used before. Hackers' devices are able to record these searches and look like the trusted WiFi networks. When these smartphones and laptops log on to the networks which are not real, hackers can easily steal their private information.

    So next time, when we want to use our laptops or our smartphones in public places which offer free WiFi networks, please think it twice or take safe measures before using them.

    What do you think the future will be like? Here are some answers from some students.

    Mary: Everyone will have a computer at home. There will also be many machines in the future. Then people will work only two or three days in a week.

    Jack: The weather in the future will be very hot. People can't live on the earth. They will have to look for (寻找) another planet to live on.

    Linda: I think the life in the future will be nice. There will be a lot of flowers and trees. And cities will look like parks.

    Henry: Every family will have a family doctor, so people will be seldom ill (很少生病) They will live to 120 years old.

    Imagine a perfect day: the weather is good and everything seems fine. When, suddenly, your mobile phone loses its signal, the television has no programs, and you can't get online with your computer.

    What has happened? These are just the types of problems a solar storm（太阳风暴）might cause. You may not think of storms as putting our society in danger. But today, a solar storm is as serious as other bad events, such as earthquakes.

    A solar storm is caused by solar flares（太阳耀斑）: large explosions（爆炸）near the sun that can give off lots of energy. The strong energy can stop the satellite systems（卫星系统）that control our computers, telecom networks and so on. These storms can even cause the power to go out for weeks or months.

    In the past few months, scientists have recorded some of the strongest sun flares in years. The most recent one happened around Valentine's Day, 2011. It caused radio and satellite signals to go down in some northern cities in China.

    “Solar flare activity is going to be much worse than what we've seen in the past. We're not talking about a few cities losing power, it could be half of the country, maybe more.” SolarStormWarning.com, a US website about space weather, warned.

    Scientists say that little can be done to predict such a storm. Governments around the world are trying to work together before the next storm, although they are not sure when that may happen.

    Do you know the whales in the sea? There are many relatives(亲属) in the whale family and they always live together with whales.

    Few people know dolphins(海豚) are part of the whale family. Dolphins are not fish. They are mammals(哺乳动物). They breathe air, and they have babies and feed them with milk. Dolphins are famous for their wonderful shows. They can jump high out of the water and show turns in the air. These jumps give the dolphins time to breathe.

    Porpoises(鼠海豚) are also in the whale family and are quite like dolphins. But they are different in the size and shape of the mouth. The dolphin's mouth is long and thin, but the porpoise's is short and thick. Dolphins are also more talkative than porpoises. Dolphins make sounds to talk with each other under water. But porpoises do not do this. Both of them are smart and friendly to humans.

    Not all the members of the whale family are friendly. Big whales are much easier to be angry than smaller dolphins or porpoises. An angry whale can be dangerous. Perhaps this helped to create the story of Moby Dick that sank (使下沉) a ship and made all the people on it die in the sea.

    What was discovered by accident? The answer is penicillin (青霉素). It kills germs. By killing germs, it saves lives. Suppose you are sick. You go to a doctor. She examines you. She says you have a “staph” infection (葡萄球菌感染). She gives you some medicine. You take it. The medicine knocks out the staph. Soon you are well. Before penicillin, this would not happen. Staph was almost sure death.

    Everyone wanted a medicine. Laboratories worked day and night. They grew the staph in small dishes. Then they tried to kill it. Nothing worked.

    The laboratory dishes had covers on them. They kept things from falling into dishes. Molds (霉菌) were a big worry. They are always in the air. You can't see them. They're too small. There are thousands of different molds. Molds can make an experiment (实验) fail. That's why dishes are covered.

    Dr. Alexander Fleming was working to kill the staph germ. He worked for years. One day he took a cover off a dish. He looked inside. There was a thick growth of staph germ. There was also some mold. Then he saw something strange. Where the mold was, there was no growth of staph. This is what Fleming probably thought. “By accident, I found a mold to kill the dreaded staph.”

    This is how penicillin was found. But here's the real miracle (奇迹). There are thousands of kinds of molds. But only one kind can kill staph. The mold must have fallen into the dish a few days before. The cover was probably off only a few seconds (秒). In those few seconds the right mold fell into the right dish. Another man might have thrown the dish away. But Fleming was very careful and smart. He understood what the mold did. How lucky the humans were!

    Smartphone apps certainly make our lives easily. However, sometimes they can also cause problems.

    Recently, the Ministry of Education(教育部) announced that teacher should not use Wechat or QQ to give homework or ask parents to grade kids's homework.

    Many teachers in China depend heavily on apps to give homework. The kids have to do their homework, stare at a phone screen. For example, Liu Yanming, a sixth-grade student in Shanghai, usually has to use his mother mobile phone to do his homework. Liu Yong, his father is afraid that apps could distract kids by encourage them to watch something unrelated(无关) to homework. "He is just 12 years old, and I do not want to buy him a cellphone," Liu told China Daily. "I also worry that my son's eyesight will be hurt because of staring at the phone for too long."

    However, Bai Yueping, president of Shanghai Tangzhen Middle School, defended (辩护) using apps for homework. Parents can understand their kids' learning situation and supervise (监督) them to finish the homework, Bai told China Daily.

    Zhang Siqi is a student from Renmin University of China.       "The use of WeChat or QQ to give homework is convenient," Zhang told China Daily. "We're living in an Internet era （时代）. It's unwise to refuse to take advantage of technology."

    Chu Zhaohui, a researcher at the National Institute of Education Sciences, believed that it is impossible to stop the use of electronic devices(设备) in the Internet era. However, students should use them when it's necessary, such as when they do listening exercises. "We don't want to stop outline education models, but they must be used carefully. Modern technologies are good... but they should not steal the show(喧宾夺主) ," he told China Daily.