地球站天线中，双工器的作用是（）.
A.将收、发信号分开
B.放大接收到的信号
C.去除信号中的噪声
D.放大上行信号
参考答案：A
取出直角三角尺（30度、60度、90度），进行操作观察：
将三角尺的一条直角边平放在桌面上，以另一条直角边为轴作快速的旋转，看到了什么？试画出示意图．怎样旋转后图形的底面积才会最大？
John Black, a new client, who has been a chargeable person for a number of years, has asked you to explain the following, with reference to income tax.
(a) The rules applicable in determining the amount of preliminary tax to be paid for the tax year 2008. (3 marks)
