1. He's a hard nut to crack.

2. That's a hard nut to crack.

3. He is a hard nut to crack.

4. 22 He's a hard nut to crack.

5. It is a hard nut to crack.

6. My boss a hard nut to crack.

7. It was then a hard nut to crack.

8. Mary found knitting a hard nut to crack.

9. This problem is a hard nut to crack.

10. Where some people a hard nut to crack.

11. This is really a hard nut to crack.

12. Jeff: This is indeed a hard nut to crack.

13. They say that she is a hard nut to crack.

14. This problem is going to be a hard nut to crack.

15. When I meet a hard nut to crack, it will help me.

16. The third question in the examination is a hard nut to crack.

17. I asked them for the money, but they were a hard nut to crack.

18. “Cultural and social values” are usually based on deep-seated tradition—a hard nut to crack.

19. One glance was all it took to realise this was one hard nut to crack - his features still completely impassive.

20. How to tackle the non-performing asset is a hard nut to crack for bank industry all over the world.

21. Screed is an important part of a paver. Welding distortion and difficulty to ensure machining accuracy have been a hard nut to crack in manufacturing processes of screeds.