to challenge sb about sth or to challenge sb on sth or to challenge sb over sth就某事向某人提出异议
I challenged him on the hypocrisy of his political attitudes.我就他虚伪的政治态度质问他。
Challenged over the methods used, the manager claimed they were permissible under existing legislation.在使用的方法受到质疑后, 经理声称这是现行法律允许的。