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问题 不定项选择题

甲烷分子是以碳原子为中心的正四面体结构而不是正方形的平面结构，其理由是 [ ]

A．CHCl3只有一种结构

B．CH2Cl2只有一种结构

C．CH4是非极性分子

D．CH4的四个价键的键长和键能都相等

答案

答案：B

单项选择题

One-year-old Susan, the second child to have sickle cell disease in a family of five children, is admitted to the hospital with sickle cell crisis. When preparing the plan of care for her, which of the following treatments would the nurse most likely expect to include in the plan

A. Intravenous fluid therapy.
B. Fast-acting anticoagulant therapy.
C. Parenteral iron therapy.
D. Exchange transfusion.
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单项选择题

环境管理体系的模式建立在一个由（）诸环节构成的动态循环过程的基础上。

A．策划、实施、检查、评审和改进

B．发起、实施、检查、评审和改进

C．策划、发起、检查、评审和改进

D．策划、实施、评审、检查和改进
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