8hm2=____m2
1900hm2=____km2
(注:1hm2 =1公顷)
下列哪项不是青春期发育的特点( )
It is difficult for us to imagine_____ life was like for slaves in the ancient world.
台湾的农产品中,具有世界意义的品种有____、菠萝、____和____等.