1. He knelt down by her, embracing her and apologizing.
    他在妻子身边跪下，抱住她，向她道歉。

2. Laughing but with tears pouring down her cheeks, she knelt down to kiss the urchins.
    她笑着，但是泪水顺着她的脸颊流了下来，她跪下来亲这些淘气包们。

3. I knelt on one knee over him.
    我单膝跪在他旁边。