Father's Day has a very short history. It was started because there was a Mother's Day, and just because some Americans thought that if we had a Mother's Day, we should also have a Father's Day. Father's Day has become important in North America. And shopkeepers (店主) found it was a good way to get people to buy presents for their fathers, presents from their shops.

    By the way, very few countries have a Father's Day, though some have Children's Day, or a special day for boys and another for girls. More and more countries are having Mother's Day, so maybe Father's Day will also become popular before too long. Now, what do people in North America do on Father's Day? The newspapers, radios, and TV tell children what they should do—buy a Father's Day present for your father. They even tell a wife to buy a Father's Day present—not for her father but for her husband, even if he is a not yet a father. And they tell grandchildren to buy a Father's Day present for their grandfathers.

    The important thing to remember about Father's Day is that American children can show their love to their fathers in a more open way.

    It's true that every country has its customs.

    We all know that in America if people are pleased with you, they will give you a sign "OK". But maybe you don't know this sign is rude in Brazil.

    In Poland, guests usually choose flowers as presents for hostesses(女主人). Remember the number must be odd(奇数的). And the hostess doesn't hope that you remove the cover of the bunch(束) of flowers. You must be more careful when you give red roses to a woman because the red rose means love.

    In China we often hear people say that "nodding" means agreement(同意). And "shaking the head" means disagreement. But in Bulgaria they mean the opposite.

    We really need to pay more attention to the differences in customs. What's more, we should learn more about them in order to avoid embarrassment(尴尬). Do remember: When in Rome, do as the Romans do.

    Haiyan is 7 years old. Her parents gave her an iPad as a gift for her birthday. A month later，her eyesight（视力）dropped to 300 degrees. This is serious for such a young child.

    Many children in China are facing the same problem: iPad using is bringing problems to their eyesight. The problem is so common that newspapers even call the iPad the "No. 1 killer of children's eyesight!"

    "There are about 30 shortsighted children coming every day, "said Hu Dali, an eye doctor at Guiyang Aier Eye Hospital. "Half of those children have poor eyesight because they have played with phones and iPads for too long. "

    Doctors and scientists say children's vision（视觉）is not yet fully developed and their eyes get tired more easily. The screen of an iPad uses very bright（明亮的）LED backlight. If children look at an iPad screen for a long time, their eyes do not have time to rest. This will make their eyesight worse over time.

    Doctors advise that users should hold their iPads between 40-60 centimeters（厘米）away from them. The brightness of the screen should be comfortable for children. Parents should also stop their children from using an iPad for more than one hour every day.