And credit should also go to the city's cultural leaders who supported this presentation of a challenging work.

There's reason to question their readiness for the more challenging work ahead.

This building is itself a challenging work of art.

They are based on challenging work that is not regularly staged.

In middle school, for example, students can temporarily move up a level, to try more challenging work.

In some ways it remains his most challenging work to date.

Growing plants can be satisfying, often challenging work, and the results are evident.

We were doing challenging work that explored tough social and political questions.

However, this book is a major and challenging work because of the questions it raises.

Attempting to create an environment in which it is possible to find exciting and challenging work.