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问题 单项选择题

根据电子束百分深度剂量随深度变化的规律，对于深度为1cm的靶区，电子能量应选择（）。

A.4MeV

B.6MeV

C.9MeV

D.12MeV

E.15MeV

答案

参考答案：A

单项选择题

A project manager spent some days to create a multi-page document which he called project charter. The document should have been issued by the project sponsor. The sponsor found the document outsized and asked for a condensed document. Which of the following is not normally an element of the project charter ？（）

A．The formal authorization to apply organizational resources to project activities

B．Detailed control account and work package descriptions

C．The business need that the project was undertaken to address

D．The product description or a reference to this document
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单项选择题

视黄醇当量是指（）。

A.维生素A1的量

B.维生素A2的量

C.体内具有维生素A活性物质的总量

D.β－胡萝卜素的量

E.其他维生素A原的量
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