哪一种维生素一半是通过食物而来，一半是由肠内细菌合成()
A．维生素K
B．维生素A
C．维生素E
D．维生素PP
E．维生素C
参考答案：A
—Ken, ________,but your TV is going too loud.
—Oh, I’m sorry. I’ll turn it down right now.
A．I’d like to talk with you
B．I’m really tired of this
C．I hate to say this
D．I need your help
商业汇票的提示付款期限是如何规定的？
