How do you say have done a great in Spanish?

The correct translation of "have done a great" in Spanish is "han hecho un gran". Here are some examples of how you can use this phrase:

* Han hecho un gran trabajo en este proyecto. (They've done a great job on this project.)

* Realmente han hecho un gran esfuerzo en mejorar sus habilidades. (They've really made a great effort to improve their skills.)

* No puedo creer lo bien que lo han hecho. (I can't believe how well they've done.)