Can someone tell me why this script isn't working?

void Update() {
if (Input.GetMouseButtonDown(0)) {
animation.crossFade(“hit”);
}
}

Monodevelop says that there is an unexpected symbol ‘end of file’
Thank you,

careful of the spelling - 'Animation.CrossFade(“hit”);

captial ‘C’

Try changing your code to:

void Update()
{
       if( Input.GetKeyDown(KeyCode.Mouse0) )
               animation.CrossFade("hit");
}