问题
单项选择题
（）是放射性射线是否对人体造成损伤的主要原因。
A.射线类型
B.放射性活度
C.放射性元素的半衰期
D.照射剂量
答案
参考答案：D
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（）是放射性射线是否对人体造成损伤的主要原因。
A.射线类型
B.放射性活度
C.放射性元素的半衰期
D.照射剂量
参考答案：D
| 从方框中选出适当的句子补全对话 | |
| Ben: Hi, Jet. I'd like to take a trip to a foreign country this summer vacation. 1 Jet: I just came back from Hawaii. It was a business trip, 2 . Ben: I hear there are beautiful beaches there. Jet: You’re right. 3 Ben: 4 Jet: Certainly. People there are very nice to foreign visitors. They're always ready to tell you anything you want to know. You can ask them for help. Ben: 5 Jet: No, not much. I stayed for five days and spent only ten thousand dollars. Ben: That's great. I don’t think I can find a better place than it. Jet: Enjoy yourself!
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