Spanish language Q&A Forum

In the question, How would you say "There was an accident on the motorway" the nearest correct answer I can find is "Había un accidente...", and there isn't the option for preterite 'hubo'. However, because accidents are one time actions with clear beginnings and ends, it's more appropriate to use the preterite tense in this case. In fact, this particular sentence is a very common one to use when explaining the differences between the two conjugations and especially to illustrate why imperfect simply doesn't work here. 

know whether tu or usted is required.  Could it not be either, depending on the formality, which is not stated?

Could someone attempt to clear something up for me?

In a quiz question on this subject we are asked to choose subjunctive vs indicative as follows:

"Aunque no ______ (tiene/tenga) mucho éxito en general, la película me parece interesante" (Although it is not very successful in general, the movie seems interesting to me)

The hint given is that there is no doubt in the speaker's mind regarding the aunque clause.

The answer is tenga (subjunctive)

In English, even if and although have quite different connotations: even if can indicate an element of doubt, but although generally does not, so I can usually work out how one or the other determines either indicative or subjunctive in Spanish translation. But I don't understand how this phrase triggers the subjunctive in this question.

Firstly, from the hint given, the phrase doesn't necessarily imply that this is shared information (that the accompanying lesson suggests would trigger the subjunctive). This info might be known only to the speaker, so shouldn't that would point to the indicative? Secondly, if there's no doubt in the speaker's mind, why consider using subjunctive at all?