unfruitful             
adjective  formal uk/ʌnˈfruːt.fəl/ us/ʌnˈfruːt.fəl/
 无成就的,无成果的
not producing any good or valuable result
  The two sides have been involved in lengthy - but so far unfruitful - negotiations. 双方进行了漫长但至今尚无成果的谈判。 
 Synonyms: fruitlessunproductive
  不结果实的
not producing fruit or crops
  If allowed to spread too quickly, the vine will end up with a lot of bare, unfruitful wood. 如果让它过快地蔓延,葡萄树最终会有很多光秃秃的、不结果的木质枝干。 
 In the new colony the soil was unfruitful and the settlers knew nothing of farming. 在新的殖民地,土地上长不出果实,殖民者对农耕一无所知。 
 Synonym: barren
  不育的,不孕的
not producing children
  They had both agreed to adopt after two years of unfruitful marriage. 结婚两年没有生育,他们都愿意收养。 
 Synonym: barren
 - More examples
 - Our appeals to the council enforcement officers have been unfruitful.
 - The search warrant was very unfruitful because we got there too late.
 - Although now 78 years old, he has not given up his unfruitful political struggle.
 - The decision can be appealed, but typically such appeals are long and unfruitful endeavours.
 - I see little benefit in expending our resources and energies in unfruitful expeditions.