下列式子中:2,2a,3x﹣1,3s+9t,s=12ab,x+y>4,m2,代数式有( )
----Liu Mei can speak Japanese so well ! Who taught her?
----Nobody . She taught_________ .
63÷(34-25)=____
就我国温度带和干湿地区而言,连江县属于( )