Преобразуйте все исчисляемые существительные в единственном числе во множествен

Преобразуйте все исчисляемые существительные в единственном числе во множественное 1. The foot is sore 2. There is man behind you 3. This isn’t a mouse. 4. This hero is unknown. 5. The mystery of the case was revealed 6. The friend of mine is coming to stay at the weekend. 7. What is the chance of success? 7. What is the chance of success? 8. There was a small loss 9. Crime is a problem in most big cities 10. What is the criterion for this estimation?