—_____ does your father work?
—He works in a hospital.[ ]
A. What
B. How
C. Who
D. Where
答案:D
四氢硼钠
A.295~300nmB.217~220nmC.1700~1800cmˉ1D.420nmE.低40cmˉ1
对发生煤气中毒的区域应设(),防止他人误入煤气地区。