原发性肝癌的肝外血行转移最多是（）
A.肺
B.骨
C.脑
D.牌
E.胰
参考答案：A
— Sorry, I can't work out this problem.
— Try again, please. It's only difficult. [ ]
A. a bit
B. a lot
C. very
D. much
器件RD-52N/NP-F1的工作频带是（）
A．890~909MHz
B．890~960MHz
C．800~2400MHz
D．1710~2300MHz
