hi,
the followoing some examples that I don’t understand it:
It was peter’s friends…
friends is plural ,right? okay, why it must used was not were?
another ex.:
twenty galons of water is a lot of to carry
twenty galons !!! why is ?
many thanks
In “It was Peter’s friends.” the subject is the singular pronoun ‘It’. English uses ‘it’ without a specific referent as a ‘functor’ word to, for example, describe a situation. Another example is “It is raining.”. The question of agreement in number between a singular subject and a plural predicate nominative is much more complex.
“Twenty gallons of water” is treated as a quantity of water. Water is not numerable (countable), although, of course, gallons are. If you refer to a quantity of something numerable and think of each of them individually–like coins in your pocket–use a plural verb. If you think of the collection as one bunch or lump (like a million dollars), use the singular. British English treats collectives, like a committee, as plural more often than American English does.