下列有机反应属于加成反应的是( )
A:2CH3CH2OH+2Na﹣→2CH3CH2ONa+H2↑
B:CH3COOCH2CH3+H2OCH3COOH+CH3CH2OH
C:CH2═CH2+Br2﹣→CH2BrCH2Br
D:2CH3CHO+O22CH3COOH
我国的内海包括( )
—Is your brother ____(old , young ).
—Yes.
在矩形ABCD中,AD=3,CD=4,点E在边CD上,且DE=1.