Sentence examples for challenges have been from inspiring English sources

Even the toughest challenges have been met with unexpected resolve.

The challenges have been considerable.

The environmental challenges have been extensively debated.

Their challenges have been well-documented.

These challenges have been analysed and addressed.

Those challenges have been piling up for a long time.

Similar challenges have been documented in Tanzania [ 35, 36].

But the technical challenges have been a deterrent.

BUT such intellectual shifts and challenges have been the driving force of Germany's unlikely success.

The programs available and some of these challenges have been reviewed previously [2, 3].

In this paper, some of these issues and challenges have been taken up.