"The average age at which people died of heart disease are decreasing."
Can I use "is" in place of "are" ?
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Sign up to join this community"The average age at which people died of heart disease are decreasing."
Can I use "is" in place of "are" ?
"Age" alone is strictly singular. "Average" alone is an adjective.
"average age" will be pertaining to one particular thing, or in this case, a number that is the average of a set of ages at which people died of heart disease.
So since the "average age" pertains to a single number, then it should be followed by a singular verb such as is.