做对这个题目的人很少。这是一个简单的应用题，要用到书中的两个公式。
Very few students solved this question correctly. It is a very simple application question, using two formulas from the text.
研究此题目的目的是在以后的应用系统中要用集群提高系统的可靠性和可用性。
The purpose to research this subject is to apply the cluster in the application systems to increase the reliability and availability in future.
题目：下腰背部疼痛需要用强的松吗？
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