A
蚯蚓
体壁
B
鲫鱼
鳃
C
青蛙
肺与皮肤
D
家鸽
肺与气囊
A:A
B:B
C:C
D:D
我国两部专门保护未成年人健康成长的法律是( )
① ② ③ ④
His grandfather ____ ____ a lot of hardships during the war.