I need a little piece of advise.
I am not sure about the right tense to use in a two clause sentence with the same subjects and before.
Please, look at the two sentences below and the use of tenses.
Before they started working, they discussed about economics.
vs
Before they started working, they had discussed about economics.
I do personally think that the second sentence is better than the first one because of the choice of the past perfect tense. -> they had discussed BEFORE they started to work.
However, my grammar book suggests that, in this kind of sentences, I should use the former.
What's your take on this?