I failed to understand what he meant.

我未能理解他的意思。

I failed the first time I tried to make egg custard.

我第一次尝试做蛋羹时失败了。

I failed the captcha three times before I got it right.

我在正确输入之前失败了三次验证码。

I was trying to place an order on your website, but I failed.

我试图在您的网站上下订单，但我失败了。

I failed my physics exam, but I passed chemistry.

我物理考试不及格，但化学及格了。

And I failed a lot.

我屡战屡败。

I tried in January. I failed.

1月份尝试了，再一次失败。

I failed in physic exam.

我物理考试又挂了。

I failed to pay my dues.

我欠缴社费.

I tried in November. I failed.

我11月份尝试了，失败了。