"a futile effort"
"the therapy was ineffectual"
"an otiose undertaking"
"an unavailing attempt"
"a fruitless search"
"futile years after her artistic peak"
"a sleeveless errand"
"a vain attempt"
来自《简明英汉词典》
来自《现代英汉综合大词典》
来自《简明英汉词典》
来自《现代英汉综合大词典》
来自柯林斯例句