散装运输的商品或品质波动大的商品均不得申请免验。( )
参考答案：对
—Where is Tom? I can't find him.
—He ________in the classroom now. [ ]
A. may be
B. maybe
C. willbe
D. was
生产性粉尘按性质可分为三类，它们是( )。
A．矿物粉尘、有机粉尘及无机粉尘
B．有机粉尘、无机粉尘及放射性粉尘
C．有机粉尘、无机粉尘及混合粉尘
D．金属粉尘、非金属粉尘及有机粉尘
