题目内容
下图中左边的UML类图描绘的是设计模式中的(1)模式。右边的UML类图描述了该模式的一种应用，其中与左图中的Abstraction对应的类是(2)。
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The writer's attitude toward the direct teacher-student relationship is______.
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______.
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