I'm having an internal debate between using the plural or singular form ('is' or 'are') in the following sentence.
"400 milliliters of water is too much".
Saying "400 milliliters of water are too much." doesn't sound grammatically correct. Is this because I am declaring the entirety of the subject as a singular noun?
In contrast, what about "Two dogs are too much to take care of" vs "Two dogs is too much to take care of"?