问答题试述儿童佝偻病的发病原因及预防措施。

律师执业的法律限制有（）

新修订的《企业会计准则第9号——职工薪酬》的施行时间是（）。

根据ChinaNet和CN2骨干网命名规范，loopback的描述中，要求采用（）为首的字符串，表明该地址的功能。

预应力混凝土的预应力筋采用应力控制方法张拉时，应以（）进行校核。

UBPM板的RUN灯以2HZ的频率闪烁表示（）。

EXCEL2000图表中的坐标轴格式，用户自行设置，其中（）不能设置。

个人得奖、中奖、中彩以及其他偶然取得的所得为（）。

关于劳务分包合同中保险的表述，错误的是（）。

编制区域规划的原则包括（）。

The food we eat seems to have profound effects on our health.Although science has made enormous steps in making food more fit to eat ,it has, at the same time,made many foods unfit to eat. Some research has shown that perhaps eighty percent of all human illnesses are related to diet and forty percent of cancer is related to the diet as well,especially cancer of the colon. Different cultures are more likely to cause certain different illnesses because of the food that is characteristic in these cultures. That food is related to illness is nto a new discovery. In 1945, about 35 years ago, government researchers realized that nitrates, commonly used to preserve color in meats,and other food additives,caused cancer. Yet, these carcinogenic additives remain in our food, and it becomes more difficult all the time to know which things on the packaging labels of processed food are helpful or harmful. The additives which we eat are not all so direct. Farmers often give penicillin to beef and living animals, and because of this ,penicillin has been found in the milk of treated cow. Sometimes similar drugs are given to animals not for medical purposes,but for financial reasons. The farmers are simply trying to fatten the animals in order to obtain a higher price on the market. Although the Food and Drug Administration(FDA) has tried repeatedly to control these procedures, the practices continue. How has science done something harmful to mankind?（）