An example sentence would be like: "In the old decades, banana was the main type of food".
Is this sentence grammatically correct? If so, does the phrase "in the old decades" have similar meaning to "a few decades ago"?
An example sentence would be like: "In the old decades, banana was the main type of food".
Is this sentence grammatically correct? If so, does the phrase "in the old decades" have similar meaning to "a few decades ago"?
As multiple comments have pointed out, there is nothing ungrammatical about the sentence but it is not a common phrase. More typical ways to say this:
In earlier decades...
In the old days...
People would probably understand what you meant if you used "in the old decades" but it is recommend to use the more common phrases instead.
1- Unfortunately, decade means in English "ten years" instead of the etymological correct but forgotten "decennium". French has kept "décade = 10 days" and "décennie = 10 years", and is right.
2- "a few decades ago" is correct ; but "in the old decades" refers to nothing.