强弩之末的英文：
[Literal Meaning]
strong/crossbow/aux./end
an arrow at the end of its flight

[解释]
强大的力量已经衰弱，起不了什么作用。

[Explanation]
spent force

[例子]
经过一天的战斗，敌人已经成了强弩之末，我们可以晚上发起进攻。

[Example]
After a day's combat, the enemy had become a spent bullet and we can attack tonight.

[英文等价词]
the last of pea-time

Until this was accomplished, the Eighth Army had reached the end of its tether
在这项工作完成时，第八集团军已经是强弩之末了。

At the end of an arrow’s flight—weakened
强弩之末

Until this was accomplished, the Eighth Army had reached the end of its tether.
在这项工作完成时，第八集团军已经是强弩之末了。

Perceiving the water clear, I found the current abate
现在水已清了，我知道那急流已经是强弩之末。