Hi Clive,
I guess what struck me was “I haven’t been home since 5 months ago”. It somehow tickles my ears. I guess it depends on how the sentence or the context it’s constructed. If the sentence is modified with an adverbial phrase as follows, it would sound ok to me:
“I haven’t been home since [Aunt Barbara’s birthday] 5 months ago”. I was taught that if “since” is used as linking word between event or things happened in the past which continues to present, it is ok to use the passed time reference because it constituted one of the three main criteria which is “duration”.
Which one would you prefer if a student says:
A – I have lived in California for 5 years [since the first day I arrived the US.]
B – I have lived in California since 5 years ago.
Idiomatically, I believe A is the correct answer either idiomatically and grammatically, although both have the magic linking word [since]. The only difference is the time phrase. I don’t mean to contradict your post, just want to firm up my own knowledge.
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