1.He made a valiant attempt to rescue the child.
他勇敢地试着去救那孩子。
2.He made a valiant attempt to rescue the struggling victim.
他勇敢地试图抢救那个正在挣扎的被害人。
3.A valiant attempt to defend her babies does not deter these assailants.
虽然它极力保护孩子，袭击者依旧防不胜防。
4.It was a valiant attempt.
那是很有价值的尝试。