出口食品生产企业卫生注册证书的有效期是( )年，卫生登记证书的有效期是( )年。
A．3；5
B．3；3
C．5；3
D．5；5
参考答案：B
串级调节系统副调节器一般选用调节器规律是比例调节，主调节器用比例积分调节。
The sports meet, originally due to be held last Friday, was finally _______ because of the bad weather.
A．setoff
B．brokenoff
C．wornoff
D．calledoff
