difficult · 困难

Completing the project on time was a challenging task for the entire team.

The team faced an arduous journey while climbing the mountain in harsh weather.

She has a demanding job that requires attention to every detail of the project.

It was a tough decision to make, but it was necessary for the company's future.

The engineer solved a complex problem that had baffled the team for weeks.

The team was up against a formidable challenge that required great skill and patience.

The research went through rigorous testing to ensure its accuracy and validity.

Accepting the new role came with onerous responsibilities that few were willing to take.

Resolving the troublesome issue required involvement from multiple departments.

The athlete faced a formidable opponent in the championship final.

The construction work required strenuous effort over several long weeks.