His efforts were unsuccessful.

他的努力失敗了。

...a second unsuccessful operation on his knee.

他第二次失敗的膝蓋手術

There were reports last month of unsuccessful negotiations between guerrillas and commanders.

有報道稱上月遊擊隊和指揮官之間的談判失敗。

The difference between successful and unsuccessful people is that successful people put into practice the things they learn.

成功者與失敗者的區别在於成功者能夠學以致用。

He and his friend Boris were unsuccessful in getting a job. [+ in]

他和他朋友鮑裏斯都沒有找到工作。