秘书要认真保管企业的印章，因为印章有( )的作用。
A．修正
B．凭证
C．标志
D．保密
参考答案：B,C
— It’s burning hot today, isn’t it?
— Yes. ________ yesterday.
A．So was it
B．So it was
C．So is it
D．So it is
