若进行下列检查，可能出现异常的是
A．血糖B．尿比重C．甲状腺功能D．肾功能E．肝功能
参考答案：B
— I wonder if you can go shopping with me together.
— Sorry. I _____ a letter all the morning and haven't finished it yet. [ ]
A. am writing
B. was writing
C. have written
D. have been writing
我国数字微波通信系统的中频频率一般选用（）。
A.140MHz、70Mz；
B.100MHz；
C.10MHz；
D.35MHz
