治疗Wernicke脑病用（）
A.维生素A
B.维生素B1
C.维生素B2
D.维生素B12
E.维生素C
参考答案：B
It was very late, but the teachers were ________ working hard in the office.
A．almost
B．already
C．still
D．ever
根据规定，商业汇票的付款期限，最长不得超过( )个月。
A．3
B．6
C．9
D．12
