Question

Nosotros _____________ a las diez en punto. empezábamos empezamos

Answer 1

Answer:

They are both correct, you need more context to determine the correct answer

Explanation:

Empezábamos is the past form of the first person plural from the verb empezar (to begin), while Empezar is the first person present form. Since the rest of the predicate just says "at ten o'clock" you could speak in present or past tense and still make sense.

Answer 2

The answer is Empezamos