Are similar words second to each other? “An investigation of the effects of inhibitors on cells.” sounds awkward due to the close proximity of one “of” to another. What seems like a lot of things. “An investigation into the effects of inhibitors on cells” in this case may be better. How would one introduce an investigation into intracellular interactions? How

does non-native speakers use ‘on’ after “investigation,’ however, I’d consider that to be incorrect.