后劲的英文：
aftereffect; stamina

参考例句：

Unsustainable momentum
缺乏后劲

Measures should be taken to ensure steady and sustained development.
要采取有力的步骤，使我们的发展能够持续、有后劲。

aftereffect是什么意思：
n. 余波,后效,后果；
副作用

"Susceptibility varies, and severity increases with depth, but there are no aftereffects."
每个人的耐受阈不同，下沉愈深则症状愈严重，但不留有后遗症。

For the basin analyst a crucial question concerns the duration and nature of the after-effects of plate interaction.
对于盆地分析者来说，关键问题在于板块相互作用后效的持续时间和性质。

It declined again after a few months, and after hostilities had ceased the incident appeared not to have left lingering inflationary after-effects.
等到敌对行动结束之后，这一事件似乎并未留下持续的通货膨胀。

When he was three years old, a high fever caused him to suffer from serious polio aftereffects, and that year he was adopted by a welfare institution.
三岁时一场高烧，使他患上了严重的小儿麻痹后遗症，这一年他被福利院收养。

stamina是什么意思：
n. 耐力，毅力，持久力；精力

The husky is unequalled for stamina and endurance.
爱斯基摩犬的体力和耐性是无双的。

He runs every day to hone his stamina.
为了增强耐力，他每天都进行跑步锻炼。

You have to have a lot of stamina to be a top-class dancer.
你必须有很强的毅力才能成为一流的舞蹈演员。

You've recovered enough stamina to swing again.
你已经恢复足够的精力去再次挥杆。

He has no backbone, ie lacks stamina, perseverance, strength of character, etc
他没有脊梁骨(缺少体力