为了降低本底，γ谱仪在测量时应放置在一定厚度的哪类屏蔽室内（）。
A.铝
B.铅
C.塑料
D.木头
E.橡胶
参考答案：B
_____ you don't have my phone number, it's 780-7842. I look forward to meeting you soon. [ ]
A. In case
B. On purpose
C. As long as
D. By the way
犀牛角
