问题
单项选择题
不能使物质产生电离作用的辐射,即称非电离辐射。下列哪种不是非电离射().
A.紫外线
B.γ射线
C.激光
D.射频辐射
答案
参考答案:B
不能使物质产生电离作用的辐射,即称非电离辐射。下列哪种不是非电离射().
A.紫外线
B.γ射线
C.激光
D.射频辐射
参考答案:B
32.Communicating via E-mail is by far the most common Internet activity. You can (1) with anyone in the world who has an Internet address or E-mail (2) with a system connection to the Internet. All you need is (3) the Internet and an E-mail program Two of the most widely used E-mail programs are Microsoft’s (4) and Netscape’s Navigator. A typical E-mail message has three basic (5) :header, message, and signature. |
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