adj.单独的,独一无二的,独自的 adv.单独地,独自地,孤独地,只，只有
Don't leave a child alone in a room with an open fire.
房间里有裸露的明火时，不要让孩子独处其中。
He knew when to leave well alone and when to interfere.
他知道什么时候该适可而止，什么时候该插手干预。
He had always been an outcast, unwanted and alone.
他一直都被视为异类，无人理睬，形单影只。