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The writer's attitude toward the direct teacher-student relationship is______.
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某公司的部门(部门号，部门名，负责人，电话)、商品(商品号，商品名称，单价，库存量)和职工(职工号，姓名，住址)三个实体之间的关系如表1、表2和表3所示。假设每个部门有一位负责人和一部电话，但有若干名员工；每种商品只能由一个部门负责销售。
部门关系不属于第三范式的原因是(40)。如果用户要求得到表4所示的结果，需要(41)，并增加关系模式(42)。
________could ride bicycle at that time.
应用文理解：请根据文章内容从每道题中的四个选项中选出最佳答案。
Vitamins are important to our health. Different vitamins are found in different foods -grains, vegetables and fruits, fish and meat, eggs and milk products. So which foods should be eaten to get enough of the vitamins our bodies need？ Let us look at some important vitamins for the answer.
Vitamin A helps prevent skin and other tissues from becoming dry. People who do not get enough Vitamin A cannot see well in darkness. They may develop a condition that dries the eyes. This can result in infections and lead to blindness. Vitamin A is found in fish liver oil. It is also in the yellow part of eggs. Sweet potatoes, carrots and other darkly colored fruits and vegetables contain substances that the body can change into Vitamin A.
Vitamin BI is also called thiamine (硫胶). Thiamine changes starchy foods into energy. It also helps the heart and nervous system work smoothly. Without it, we would be weak and would not grow. We also might develop beriberi (脚气病). Thiamine is found not just in whole grains like brown rice, but also in other foods. These include beans and peas, nuts, and meat and fish.
Vitamin C is needed for strong bones and teeth, and for healthy blood passages. It also helps wounds heal quickly. The body stores little Vitamin C. So we must get it every day in foods such as citrus fruits, tomatoes and uncooked cabbage.
Vitamin D increases levels of the element calcium (钙) in the blood. Calcium is needed for nerve and muscle cells to work normally. It is also needed to build strong bones. Vitamin D prevents the children's bone disease rickets (佝偻病). Ultraviolet light from the sun changes a substance in the skin into vitamin D Fish liver oil also contains vitamin D. In some countries, milk producers add vitamin D to milk so children will get enough.
Vitamin K is needed for healthy blood. It thickens the blood around a cut. to stop bleeding. Bacteria in the intestines (肠道) normally produce vitamin K. It can also be found in pork products, liver and in vegetables like cabbage, kale and spinach.
Lack of Vitamin A will lead to______.
But the fastest-growing area for Internet spying is the home. SpectorSoft, a leading manufacturer of spyware, at first marketed its products to parents and employers. Sales jumped enormously, however, when the company changed its pitch to target romantic partners. "In just one day of running Spector on my home PC, I was able to identify my boyfriend's true personality," a message on the company's website declares.
What can you expect if someone puts SpectorSoft's Spector 2.2 on your computer？ It will take hundreds of records an hour of every website and e-mail that appears on your screen, and store them so that someone who is spying on you can review them later. A new product, SpectorSoft's eBlaster, will send the spy detailed e-mail reports updating your computer activities frequently. These products keep the people being spied on totally unaware.
SpectorSoft has sold 35,000 copies of its spyware, and it has only a piece of a flourishing market. WinWhatWhere, another big player, sells primarily to businesses, but what it calls the "discontented family member" market has been finding WinWhatWhere. Many smaller companies have sites that sell relatively crude "key-loggers," software that records every keystroke typed on a computer.
Isn't all this spying on loved ones a little creepy？ Not to SpectorSoft president Doug Fowler. "If you're in a committed relationship and you get caught because of evidence online, as far as I'm concerned you deserve to be caught," he says. Richard Eaton, president of WinWhatWhere, recognizes that in a perfect world users would reveal that they have placed monitoring software on a computer. But WinWhatWhere Investigator has a feature that allows it to be completely hidden. "Our customers demanded it," he says.
From the text we learn that most companies in the U. S.______.
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