A:CH4+Cl2 →光照 CH3Cl+HCl
B:CH2═CH2+Br2→CH2BrCH2Br
C:2CH3CH2OH+O2 →△Cu 2CH3CHO+2H2O
D: +HNO3 →50~60℃浓H2SO4 +H2O
—Shall we have a smoke here?
—No, we _____ because this is gas station and the worker is carrying some petrol.
可以作圆,且只可以作一个圆的条件是( )
如果你发现丁香花或玫瑰花叶子上有一些精致的小洞,这是樵叶蜂剪下了小叶片。