用户交寄各种不符合尺寸、纸质规格要求的明信片时，应套封后按信函交寄。
参考答案：对
锅炉水位应经常保持在正常水位线处，并允许在正常水位线上下( )之内波动。
A．10mm
B．30mm
C．50mm
D．60mm
I wonder if he _______ this weekend. If he ______, I’ll let you know.
A．will come; will come
B．will come; comes
C．comes; comes
D．comes; will come
