I finally found the right key after lots of trial and error.

经过反复试验，我终于找到了正确的方法。

youdao

Finally he found one, but so small that it could scarcely be seen. He tried the key, and fortunately it fitted.

最后他终于找到了，这个钥匙孔太小了以至于很难发现。他试了试钥匙，很幸运是合适的。

youdao

Finally he found one, but so small that it could scarcely be seen. He tried the key, and fortunately it fitted.

最后他终于找到了，这个钥匙孔太小了以至于很难发现。他试了试钥匙，很幸运是合适的。

youdao