When the telephone rang one afternoon

[Bassim]

I am wondering if my sentences are grammatically correct. I am not sure if I should write "did not imagine" or should it be " could not imagine"?

When the telephone rang one afternoon, Maria did not imagine how much that call was going to change her life. The well-known film director offered her the role in his film.

 

[GoesStation]

Write could not imagine and, unless the role was mentioned in the previous sentence, a role.

 

[Tdol]

I guess from the context that this is the first mention of the director, so I would use an indefinite article.