会的请帮忙用when/while + doing/done(壮语从句的省略造句）谢谢

When walking on the street,I saw Mr.Zhang或者 Waling on the street, I saw Mr. Zhang.
很简单，伴随状语从句，但是doing必须和主语有同一个逻辑主语，主语的主语是I,所以doing的发生动作的主语比喻也是I.
如：When walking on the street,Mr.Zhang met I.这样就不对了。

I was surprised when seeing him dancing~