I wrote an article analyzing trade figures for 2019. Originally I wrote: "We can find that only the first 3 months have their export values bigger than their import values". Upon proofreading, I was suggested to rephrase the "first 3 months have" part, because I was told that a month cannot possibly "have" something as an object that belongs to it.
I want to check if my original expression sounded natural to the native Americans or English speakers.
As a side note, I noticed a native expression that goes: "The last 3 months have seen significant development in the housing market." Perhaps this is relevant to my question here. I thought if an action word ("seen") can come right after "3 months", the "3 months" here can be regarded as a subject. If a subject can have an object, so do "3 months".