A:a+b=m+n
B:a=2m
C:a+2b=2m+n
D:n=2b
“任用管仲为相,对内整顿朝政,对外‘尊王攘夷’,终于九合诸侯,一匡天下,成就了春秋五霸之首伟业”的是( )
Hainan Island is a good place_____.