LOOK at these little ‘stories’ and see if you can find a mistake in each of them:
“My wife’s handbag with all her three credit cards, which she needed for her shopping spree, were stolen.”
“Did you report the theft?”
“Unlike my wife, the thief is not good at spending.”
The subject and verb of a sentence must always be in agreement: if the subject is singular, the verb must be singular; if the subject is plural, the verb must be plural.
The first sentence has a singular subject, “my wife’s handbag”. “All her three credit cards” is merely an additional phrase introduced by the preposition “with” after the subject.
Rewrite the first sentence: “My wife’s handbag with all her three credit cards, which she needed for her shopping spree, was stolen.”
(If we use the coordinating conjunction “and” instead of the preposition “with”, the verb becomes plural: “My wife’s handbag and her three credit cards, which she needed for her shopping spree, were stolen.”)
“Let’s hurry to the hall. David or his sisters is singing my new song right now.”
“Whenever I hear any of them sing, I always clap my hands — over my ears!”
In a sentence where the subjects are joined by “or” or “nor” and one of the subjects is singular and the other is plural, the number of the verb is determined by the subject nearer to it: David or his sisters are singing my new song right now.
The teacher asks Tommy, the only one of the pupils who have not done the homework, “What is your excuse?”
“My dog ate my homework,” the boy replies.
“And where is your dog now?”
“My mother took it to the vet’s. It doesn’t like arithmetic any more than I do.”
The first sentence should read: The teacher asks Tommy, the only one of the pupils who has not done the homework, “What is your excuse?”
In the clause “who has not done the homework”, “who” is the subject of the clause, and its antecedent is singular (“the only one”).