A:3
B:﹣3
C:13
D:﹣ 13
若m、n满足2m+1+n-22=0,则mn的值等于( )
____( she ) shirt is white.
①涡虫 ②水螅 ③水母 ④河蚌 ⑤绦虫 ⑥血吸虫