futile: may connote completeness of the failure or unwisdom of the undertaking: a ~ search for survivors of the crash.    （又如futile talk空谈，如he is a futile sort of person他是一个无用的人，如a futile attempt to achieve the impossible为办不到的事徒劳）  （undertaking事业事情a task or project, especially one that is important and difficult重大或艰巨的任务项目，同义词是venture，如he is interested in buying the club as a commercial undertaking他有意购买那个俱乐部作为商业投资(事业)，如in those days, the trip across country was a dangerous undertaking那个时期，越野旅行是一件危险的事情）


vain: usually implies simple failure to achieve a desired result: a ~ attempt to get the car started.   (如all my efforts were vain一切努力都白费了，如it is vain to resist抵抗是没用的, 如we here highly resolve that these dead shall not have died in vain决不让这些先烈的死变成白白的牺牲)


fruitless: comes close to vain but often suggests long and arduous effort or severe disappointment: ~ efforts to obtain a lasting peace.


bootless: chiefly literary, applies to petitions and efforts to obtain relief: a ~ request for aid.


abortive: suggests failure before plans are matured or activities begun: an ~ attempt to escape.     （如the doctor had to abort the baby医生不得不打掉胎儿，如the captain instructed them to abort the mission上尉指示他们中止任务）

futile徒劳无益: 表示所作的事情完全失败或不明智，vain徒劳: 仅指一般的失败，fruitless无果:  同上，但表示付出长期艰苦努力，因而失望，bootless无果: 有文学色彩，用于请愿或求援，abortive流产堕胎夭折: 表示计划还未成熟行动还未开始，即已失败


记忆方法: 1）首字母FVFBA我烦不烦啊<==无果

         2）无果的意思是没有结果mean barren of or producing no result.    barren土地贫瘠树不结果人不育