When two nouns refer to the same person or thing, the verb is in the singular form.
When two nouns refer to the same person, the article ‘the’ is used only once and the verb is in the singular.
- The nurse and sister of the patient cares deeply for him.
(Nurse and sister are the same person, singular verb cares is used.)
Not: The nurse and sister of the patient care deeply for him.
- The nurse and sister of the patient was very caring.
Not: The nurse and sister of the patient were very caring.
- The owner and occupant of the haunted house was never seen again.
Not: The owner and occupant of the haunted house were never seen again.
When two nouns refer to two different persons, the article ‘the’ is repeated and the verb is in the plural
- The owner and the occupant of the house are very good friends.
The teacher and the father of the student are talking about him.
An amount regardless of how much it is, and measurements of weight and distance are followed by a singular verb
- The fifty dollars you lent me was not enough.
- Two hundred dollars nowadays is not a big sum.
- How many cents is equal to one dollar?
- She said seventy kilograms was her weight.
- Five kilograms of flour is enough for baking the cakes.
- Two litres of oil was used to fry those things.
- Ten kilometres is a long distance to walk.
- According to the survey, 54% of the people are going to vote for him.
(People is a plural noun and 54% of the people must therefore take a plural verb.)
- Only fifteen percent of the building was damaged in the fire.
(Building is a singular noun and 15% of it is singular and takes a singular verb.)