The combination of singular and plural in the English sounds odd to me here. I would write either "Is the second a unit of time" or "Are seconds units of time?"
Terima kasih Pak James.
Your suggestions are added to the list of acceptable answers.
But why my answer is still considered wrong?
Oddly enough, my brain thinks "Are seconds a unit of time" is ok, despite it obviously not agreeing on number.
Are seconds a unit of time
Duo Lingo, Please have a look
Is second a unit of time should also be correct
I think 'measure' can be a synonym of 'unit' even though we have ukuran for the former and satuan for the latter