having seen him
Seeing him, she smiled.
Were you surprised to see him?
Увидев его лицо, она заплакала.
Seeing his face, she began to cry.
Увидев его, я не смог сдержаться от смеха.
When I saw him, I couldn't help but laugh.
Я не мог удержаться от смеха, увидев его.
I couldn't help but laugh when I saw him.