手术器械和敷料的常用灭菌方法是
A. 紫外线消毒
B. 乳酸消毒
C. 高压蒸气灭菌
D. 甲醛熏蒸法
描述一组偏态分布资料的变异度，以下列哪项指标为好
A. 变异系数(CV)
B. 标准差
C. 极差(R)
D. 四分位间距(QU—QL)
E. 以上都不是
______ you eat the correct foods ______ be able to keep fit and stay healthy.
A. Only if; will you
B. Only if; you will
C. Unless; will you
D. Unless; you will
Though having lived abroad for years, many Chinese still ______ the traditional custom.
A. perform
B. possess
C. observe
D. support
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