将某个频带列入频率划分表，规定该频带可在指定的条件下供一种或多种地面或空间（）业务或射电天文业务使用，称为频带划分。
参考答案：无线电通信
跨省粮食收购者应当向什么部门定期报告粮食收购数量等有关情况？
---It's very kind of you to see me off,Mr Johnson.
---______.It's the least we could do.
A．That's true
B．Not at all
C．I don't think so
D．Don't say to
