He was the first person to openly challenge the system.

This was not the first time she had openly challenged the university.

And she is one of the few people who openly challenges the mayor.

His remarks caused one professor to walk out and another to openly challenge them.

She realized that the public relations director was openly challenging her.

It openly challenged the ideals of the movement and its organization.

Now, they are openly challenging him and, in the process, revealing their frustration.

But he openly challenged the general, a major American ally in the campaign against terrorism.

Maybe he should be careful of any advice received, without openly challenging its validity.