In a correctly written sentence, the subject and verb agree (match) in number. Singular subjects require singular verbs; plural subjects require plural verbs. This applies to sentences written in the present tense. (Past tense forms of regular verbs require “ed,” and past tense forms of irregular verbs usually require a change in spelling.)

Examples:
The lady dances beautifully. (Singular)
The ladies dance beautifully. (Plural)

A man stands outside the shop all day. (Singular)
Two men stand outside the shop all day. (Plural)

Jason writes well. (Singular)
Jason and Chris write well. (Plural)

My English instructor has a master’s degree. (Singular)
My English and history instructors have graduate-level degrees. (Plural)

Take a moment to look at the conjugated verb on p. 419. Notice that with a regular verb (leap), the only time you need to add –s to the verb is when the subject is he, she, it, or a word that can be replaced with he, she, or it (3rd person, singular form). For instance, in the examples above, “lady” can be replaced with the pronoun “she,” so you need an –s on the verb—dances. Since “ladies” is plural and can be replaced with “they,” you need the plural verb form—dance. Notice that singular verbs end in –s; plural verbs do not. 

Compare the conjugation of “to leap” to the following chart.

Note irregular forms of “to be,” “to have,” and “to do.”

Singular		I 		       work / study / am / have / do          
			You 		       work / study / are / have / do
			He, She, It	        works / studies / is / has / does

Plural			We		       work / study / are / have / do
			You		       work / study / are / have / do
			They		       work / study / are / have / do

Now this only works with regular verbs. Irregular verbs change form (even in the present tense sometimes).
See p. 421.

Examples: 

My sister is coming to visit this weekend. (“is” is a form of “to be”)
Mom and Dad are coming to visit this weekend.

Michael’s roommate has a huge bedroom.
Michael’s roommates have to share a bedroom.

Each student does his/her own assignment.
The students do their assignments in groups.

Notice that even with these irregular verbs, the singular form still ends in –s (is, has, does). This might help you distinguish between singular and plural forms.
Once you understand basic subject-verb agreement, you are ready to look at situations that can pose problems in making subjects and verbs agree. This is where the skill of identifying subjects and verbs comes into play. 

Basic Subject-Verb Agreement: p. 420
One student listens attentively to the lecture. (“Student” is singular and can be replaced with “he/she,” so a singular verb is used. Singular verbs end in “s” with 3rd person subjects.)
The students listen attentively to the lecture. (“Students” is plural and can be replaced with “they,” so a plural verb is used – without an “s.” Plural verbs never end in “s.”)
The computer is broken. (Not be) (“Computer” is singular and can be replaced with “it,” so a singular verb is used.)
The computers are broken. (“Computers” is plural and can be replaced with “they,” so a plural verb is used.)
Each e-book (cost / costs) $100. (“e-book” is singular and can be replaced with “it”; thus, the verb ends in “s.”) 
My e-books (cost / costs) $500. (“e-books” is plural and can be replaced with “they”; the verb should not end in “s.”)
Jason and Mark (share / shares) an apartment. (“Jason and Mark” is a plural compound subject; a plural verb is used.)

Special Singular Constructions: p. 423
Most indefinite pronoun subjects require singular verbs. (Any word ending in one, body, or thing is singular: anyone, anybody, anything/someone, somebody, something/ everyone, everybody, everything/nobody, no one, nothing—PLUS either, neither, each, & every.)

Nobody understands the assignment.
  
Everyone knows how to use Canvas.

If anyone needs help, he or she should ask the instructor. (Note pronoun-antecedent agreement—he or she.)
Someone (does / do) all of Jason’s work for him. (“Someone” is a singular indefinite pronoun & requires a singular verb.)
Neither of the students (has / have) an access code. (“Neither” is a singular indefinite pronoun & requires a singular verb.)

NOTE: While most indefinite pronouns are always singular (each, everyone, somebody), a few are not. 
~The pronouns both and a few are always plural and require plural verbs:
Both of my uncles play the piano and sing professionally. 
A few of my cousins are also performers.

~The pronouns all and some are either singular or plural, depending on the words that follow them. If the words after them are singular, they are singular. If the words after them are plural, they are plural. This is the only time you need to be concerned with what appears in a prepositional phrase in order to determine agreement.

Some of the birthday cake is still on the table. 

(“Cake” is singular – Some of it is….)

Some of the party guests are not having any dessert. 

(“Guests” is plural – Some of them are….)
~Another exception to the “Indefinite pronouns are singular” rule is the case in which two subjects are joined by “neither . . . nor” OR “either . . . or.” When this occurs, look at the subject closer to the verb to determine agreement. p. 424
Neither the students nor the teacher understands the question. (“Teacher” is closer, so a singular verb is used.)
Neither the teacher nor the students (understand / understands) the question. (“Students” is closer, so the plural 
                                                                                                                                       verb is used – without an “s.”)

~The same rule applies when two subjects are combined by “or” OR “not only . . . but also.”

My sister or my parents visit me every weekend. (“Parents” is closer, so the plural verb is used.)
My parents or my sister visits me every weekend. (“Sister” is closer, so the singular verb is used.)
Not only my parents but also my sister (visits / visit) me every weekend. (“Sister is closer, so the singular verb is used.)

Collective Nouns: (not in Ch. 29 but in Ch. 33 – p. 466)
Collective nouns represent a group of people but are usually considered singular and require singular verbs; a few are team, class, committee, jury, audience, government, company, group, and family.

The Johnson family is planning its annual reunion. (“Family” is singular and requires a singular verb phrase.    Note pronoun-antecedent agreement as well – its.)

The committee meets every Tuesday morning. (The “committee” is one unit and is, thus, singular.)

Separation of Subject & Verb: p. 425
(Note the prepositional phrase “in one of my classes” in the first example.  Do not let that confuse you. Nothing within a prepositional phrase can be the subject, so if you cross it out, you are left with “A girl comes in late every day.”)

A girl in one of my classes comes in late every day. (“Girl” is singular and requires a singular verb.)

Three people in my math class come in late every day. (“People” is the plural subject and requires a plural verb.                                                                Ignore the prepositional phrases.)
The instructors of my math class and English class (is / are) part-time instructors. 
(“Instructors” is plural and requires the plural verb “are.” Ignore the prep. phrase “of my math class and English class.”)

The guy in the red shirt (has / have) my books. (“Guy” is singular and requires the singular verb “has.”)

Sentences beginning with There and Here: pp. 425-26
In sentences that begin with there or here, the subject usually follows the verb:

Here is the handout you need. (“Handout” is a singular subject and requires the singular verb “is.”)
Here are the papers the instructor needs. (“Papers” is a plural subject and requires the plural verb “are.”)
There (goes / go) my roommate. (“Roommate” is a singular subject and requires the singular verb “goes.”)
There (goes / go) my roommates. (“Roommates” is a plural subject and requires the plural verb “go.”)
Agreement in Questions: p. 426
In questions, the subject usually follows the verb:

Where is the book you promised to bring? (“Book” is a singular subject and requires the singular verb “is.”)
Where (is / are) the books you promised to bring? (“Books” is a plural subject and requires the plural verb “are.”)
Have you bought your access code? (“You” is the 2nd person subject and requires the verb phrase “have bought.”)
(Has / Have) the students responded well to Aplia? 
(“Students” is a plural subject and requires the plural verb phrase “have responded.”)

(Has / Have) the instructor offered any bonus points? 
(“Instructor” is a singular subject and requires the singular verb phrase “has offered.”)

NOTE: There are other instances in which the subject comes after the verb: Ch. 16
At the front of the room are several pieces of instructional equipment. (Ignore the prepositional phrases.)
At the back of the room (sit /sits) several broken desks. (“Desks” is the plural subject and requires the plural verb “sit.”)
On top of the filing cabinet (is / are) some extra paper. (“Paper” is a singular subject and requires the singular verb “is.”)

Agreement in Relative Clauses: p. 427

Most patients prefer doctors who spend time talking with them. (The verb in the “who” clause agrees with “doctors.”)
Laptop computers, which have some advantages over desktop computers, are becoming more popular.  
(The verb in the “which” clause agrees with the “computers.”)

Employers often appreciate an employee who (asks, ask) intelligent questions. 
(The verb in the “who” clause should agree with “employees.”)

Foods that (contains, contain) artificial sweeteners may be hazardous to your health. 
(The verb in the “that” clause should agree with “Foods.”)

PRACTICE
1.	Since my dentist filled two cavities in my teeth, I (does / do) not mind brushing.
2.	The parents (was / were) impressed by the teacher’s commitment to her students.
3.	Johnny’s mother often (criticizes / criticize) his poor performance at work.
4.	Near the center of the town (stands / stand) a statue of the town’s founder. 
5.	The clowns with the large hats (is / are) amusing to the children.
6.	Where (was / were) the cat and dog sleeping before you purchased the cages?
7.	Sheila and Jan (stays / stay) at home until their mother arrives.
8.	Neither of the boys (has / have) enough money to buy lunch.
9.	Either Mike or another player (waits / wait) for the coach after practice.
10.	Everybody in the class (plans / plan) to attend graduation.
11.	A sports team (offers / offer) a lot of opportunities to meet other people.