the amphibians use lungs and their ???? to breathe

比一個例子你就明

完全成長嘅墨西哥蠑螈，大概需要18至24個月。體長150毫米至450毫米（6至18英寸），正常嘅體長係230毫米（9英寸），體長長過300毫米（12英寸）係好少有嘅。佢哋有獨特嘅類似蕨類植物嘅唔封閉 腮 結構（同魚、蝌蚪嘅腮一樣）。通常由6條腮平均分布喺頭部兩側，每邊3條。腮一般係紅色，但已知會隨住食物嘅顏色改變。如果佢食紅色肉類，腮就會變成紅色。墨西哥蠑螈同樣會用皮膚呼吸，再將空氣轉入肺部。佢啲牙細到好難被察覺到，一般係用嚟夾住食物而唔係用嚟撕裂同咀嚼食物。佢哋有快速嘅身陳代謝，可以好快咁重新長出肢體或者器官。


所以amphibians係用Lung and腮黎呼收............因為全要睇隻生物係邊度，如果係陸地就會用皮膚呼吸，係水就會用腮呼吸

When they are young, they use gills for gaseous exchange (like fish), but when they are adult, they develop lungs for breathing, but at the same time they can also use their moist skin to facilitate gaseous exchange.
So the answer for your question should be skin. But it is indeed not a very good question.