经过多次尝试，他终于学会了游泳。

After many ___attempts, he finally learned how to swim.

她尝试了几次都失败了，但并未放弃。

Her ___attempts to solve the puzzle failed several times, but she didn't give up.

登山者们多次尝试攀登那座险峰。

The climbers made several ___attempts to scale the dangerous peak.