Could this also be 'we open our buildings for the local community'?
Cool, thanks. I guess that needs to be added as a correct answer then (I'm not sure how to get back to the question to suggest it)
Neither am i. I think that happens just by redoing the same set of exercises or wait for the sentence in the future (it may appear sometime). But you'll find more bugs worth reporting ;) when you do that you'll be helping new learners!