I are on a bus. (?)
I are on the journey. (?)
A subject is the noun or pronoun ( or person, place or thing ) the sentence is about.
What is the verb action word that goes with the subject I?
So the sentences should be -
I am on a bus .
I am on the journey.
➤ Rule 1: The noun having ics at its end will take singular verb .
Optics is an important subject.
➤ Rule 2: A verb must agree with its subject in person and number .
The linking verb be , however , changes form in both present and past tense.
Singular : She reads . It was right.
Plural : They read. They were right .
When be , have and do are used as auxiliaries in verb phrases , their form changes to show agreement with third person subject .
Singular : She is singing . He has gone away. Rana does work here .
Plural :They are singing . They have gone away. They do work here.
But -
We do not mistake a word in a prepositional phrase for the subject of a sentence. We never confuse the subject with a prepositional phrase that follows .
Example -
The author of the stories uses a pen name.
A letter with many mistakes does not make a good impression .
( the subject letter is singular , with many mistakes is a prepositional phrase . Therefore, the verb does agrees with the singular subject letter.)
➤ Rule 3: Plural verb is used after the phrase a number and after the number singular verb is used .
A number of persons were killed in the accident .
The number of students in this class is 50.
➤ Rule 4: Although the name of a book is plural in form , a singular verb will be used for it.
Gulliver's Travels is a famous book.
Great Expectations was written by Dickens .
➤ Rule 5: The nouns which indicate group of persons /animals/things will take either singular or plural verb.
🔷 The government has introduced compulsory primary education.
🔷 The government have introduced compulsory primary education.
The academic committee was annoyed with the chairman .
The academic committee were annoyed with the chairman .
➤ Rule 6: In an inverted sentence (a sentence in which subject follows the verb , that is, a subject is placed after the verb), we must take care in locating the simple subject , and make sure that the verb agrees with the subject.
Example-
Singular : From the branch sings a bird .
Plural : From the branch sing two birds.
Some inverted sentences begin with the word here and there .
Singular : There goes the trainer.
Plural: There go the two trainers.