when asked：是省略句的形式
例如：when asked his success， he owed it to the support of his wife.
英语连词：when while if once unless though although as if 当主句与从句主语相同，并且从句含有be动词，此时，可以把从句的主语跟be动词省略。形成下列的结果
连词+doing/done/介词短语/形容词
例如：while walking the dog， he was careless and it gotloose。
