Past Imperfect vs Past Imperfect + Gerund

The hint indeed suggests using the pretérito imperfecto (temblaba) rather than the continuous form (estaba temblando). Let’s clarify the difference between these two:

1. Pretérito Imperfecto (temblaba): This tense describes a past action that was ongoing, habitual, or without a specific end. When we say "temblaba", it implies that the shaking was happening as a general, continuous state without focusing on the process.

2. Pretérito Imperfecto Progresivo/Continuo (estaba temblando): This form (also called the past continuous) emphasizes the ongoing action itself, as if focusing on the process in progress at a particular moment. "Estaba temblando" would imply that we are observing or focusing specifically on the act of shaking at that moment, almost like viewing it in action.

In many cases, both are valid. However, "temblaba" is more commonly used to describe states or general conditions in the past without focusing on the progression of the action. "Estaba temblando" can be more appropriate when you want to emphasize the duration or ongoing nature of the action at a specific time.

So, yes, "estaba temblando" is a valid answer, but "temblaba" aligns more closely with the intended usage in this context, as it describes the shaking as a general past condition without highlighting the action’s progression.

Let me know if this helps or if you have more questions!

Saludos

Silvia