After the heavy rain, _____ trees are dry.[ ]
A. few
B. a few
C. little
D. a little
答案:A
可列反应是加成反应的是( )
A.CH4+Cl2光照CH3Cl+HCl
B.CH2CH2+Br2→CH2BrCH2Br
C.2C2H5OH+O2△2CH3CHO+2H2O
D.C2H6+Cl2光照C2H5Cl+HCl
形成急性血源性骨髓炎大块死骨的原因主要是()
A.骨膜掀起、骨膜血管断裂
B.骨膜掀起、骨膜血管断裂和骨的滋养血管栓塞
C.脓肿直接破坏骨组织
D.病理骨折
E.骨的滋养血管栓塞