（）是中国古代最早的官修韵书，也是现存最早的完整韵书。
A.《韵集》
B.《广韵》
C.《切韵》
D.《声类》
参考答案：B
I hear they've promoted Tom．but he didn't mention ______ when we talked on the phone．
A．to promote
B．having been promoted
C．having promoted
D．to be promoted
Various optional courses being available, we can choose ________ based on our own interest.
A．either
B．each
C．one
D．it
