**Here are 10 examples of using the word «challenging» in English:**
1. It was a challenging task to complete the project within such a short deadline.
2. Raising awareness about climate change is a challenging issue that requires collective effort.
3. Learning a new language can be a challenging but rewarding experience.
4. My boss assigned me a challenging project that pushed me to work harder and improve my skills.
5. Running a marathon is a physically and mentally challenging activity.
6. Dealing with a difficult customer can be a challenging situation for a salesperson.
7. My friend and I decided to go hiking in the mountains, and it was a challenging but beautiful journey.
8. Starting a business can be a challenging process that requires careful planning and dedication.
9. The teacher assigned us a challenging math problem that took us hours to solve.
10. My coach challenged me to improve my fitness level by running longer distances every week.