Essential English Grammar Rules

A practical reference to the most important English grammar rules. Each section covers a rule, the correct pattern, common mistakes, and exceptions.

Subject-Verb Agreement

The verb must match the subject in number — singular subjects take singular verbs, plural subjects take plural verbs.

Exceptions:

• “None” can take singular or plural: None of the water is left. / None of the students are here.
• “Each” always takes a singular verb: Each student has their own laptop.
• “The number of” → singular; “A number of” → plural: The number of errors is low. / A number of errors were found.

Article Usage: A, An, The, and Zero Article

Key distinctions:

Fixed expressions:

• No article: go to school, at home, by bus, in bed, at night
• Definite article: the radio, the internet, the government, the environment

Prepositions of Time, Place, and Movement

Time

Place

Movement

Common mistake: go to home → go home (no preposition with “home”).

Tense Usage: Present Perfect vs Past Simple

Wrong: I have seen that movie yesterday. → I saw that movie yesterday.

Present perfect continuous emphasizes the duration or recentness of an activity:

• I have been working here for five years. (emphasizes ongoing nature)
• I have worked here for five years. (emphasizes the fact)

Conditionals

Common errors:

• Using “will” in the if-clause: If I will see him, I will tell him. → If I see him, I will tell him.
• Using “would” in the if-clause of second conditionals: If I would be rich, I would buy a house. → If I were rich, I would buy a house.
• Note: “If I were” (subjunctive), not “if I was”, though “was” is accepted informally.

Alternatives to “if”:

• Unless (= if not): Unless you hurry, we will be late.
• As long as / provided that: You can borrow the car as long as you drive carefully.
• In case of + noun: In case of fire, leave the building.

Relative Clauses: Defining vs Non-Defining

Examples:

• Defining: The students who arrive late will be marked absent. (only those late students)

• Non-defining: The students, who arrived late, were marked absent. (all students were late)

• Defining: The car that is parked outside belongs to my neighbor.

• Non-defining: My car, which is parked outside, belongs to my neighbor.

Whose for possession: The man whose wallet was stolen called the police.

Where / When / Why for place, time, reason:

• The restaurant where we met has closed.
• The year when I graduated was 2020.
• The reason why I left is personal.

Passive Voice

Form: be + past participle

When to use passive:

• The agent is unknown: My bike was stolen last night.
• The agent is obvious or unimportant: The suspect was arrested.
• The action matters more than the doer: The report was submitted on time.

To include the agent, use “by”: Hamlet was written by Shakespeare.

Common mistake: The door was opened with him. → The door was opened by him.

Reported Speech

No backshift is needed when the situation is still true or reporting immediately:

• She said she is tired. (still tired now)
• He said the Earth is round. (universal truth)

Questions in reported speech use statement word order (not inversion):

• “Where do you live?” → He asked me where I lived. (not where did I live)
• “Are you ready?” → She asked if I was ready.

Commands: “Sit down.” → He told me to sit down.

Requests: “Please help me.” → She asked me to help her.

Question Formation: Subject vs Object Questions

Subject questions ask about the subject — do not use do/does/did:

• Who called you? (subject = who)
• Which train arrives first? (subject = which train)

Object questions ask about the object — use the auxiliary do/does/did:

• Who did you call? (subject = you, object = who)
• Which book did you read? (subject = you, object = which book)

Tag questions:

• Positive statement → negative tag: You are coming, aren’t you?
• Negative statement → positive tag: You aren’t tired, are you?
• With “I am”: I am right, aren’t I? (not amn’t I)
• With imperative: Open the door, will you? / Don’t be late, will you?

Countable vs Uncountable Nouns

Nouns that can be both:

Common uncountable nouns (no “s”):

• Information, advice, knowledge, news, furniture, luggage, equipment, research, progress, traffic, weather, work, money, music, bread, water

Common mistake: informations → information; advices → advice; furnitures → furniture

To quantify uncountable nouns, use a piece of / a bit of / an item of:

• a piece of information / advice / news
• an item of furniture / luggage / equipment
• a drop of water / oil / rain
• a slice of bread / cheese / cake

Practice Exercises

Exercise 1: Subject-Verb Agreement

Choose the correct verb form.

1. The group of students (is / are) waiting outside.
2. Neither the teacher nor the students (know / knows) the answer.
3. Everyone (has / have) completed the assignment.
4. Ten miles (is / are) a long distance to walk.
5. Each of the players (deserve / deserves) a trophy.

Exercise 2: Articles

Fill in a, an, the, or ∅ (zero article).

1. I need ___ new laptop. ___ laptop I have is too slow.
2. She is ___ honest person. She never lies.
3. ___ dogs are ___ loyal animals.
4. He works as ___ engineer at ___ large company.
5. We had ___ breakfast at ___ hotel, then left for ___ airport.

Exercise 3: Prepositions

Fill in at, on, in, to, for, since.

1. I have been waiting ___ 9 AM.
2. She arrived ___ the airport just ___ time.
3. We usually go ___ the park ___ Sunday afternoons.
4. He has lived here ___ three years.
5. The cat jumped ___ the table and knocked over ___ vase.

Exercise 4: Tenses and Conditionals

Complete with the correct form.

1. If I ___ (know) about the party, I would have come.
2. She ___ (work) here since 2022.
3. If you heat water to 100°C, it ___ (boil).
4. I ___ (finish) the report, but I haven’t had time.
5. If I ___ (be) you, I would accept the offer.

Exercise 5: Active to Passive

Rewrite in passive voice.

1. Someone stole my wallet.
2. The chef prepares the meals.
3. They will announce the winner tomorrow.
4. The mechanic has fixed the car.
5. Students must complete the form.

Answer Key

Exercise 1: 1. is, 2. know, 3. has, 4. is, 5. deserves

Exercise 2: 1. a / The, 2. an, 3. ∅ / ∅, 4. an / a, 5. ∅ / the / the

Exercise 3: 1. since, 2. at / in, 3. to / on, 4. for, 5. onto / a

Exercise 4: 1. had known, 2. has been working / has worked, 3. boils, 4. would have finished, 5. were

Exercise 5: 1. My wallet was stolen. 2. The meals are prepared by the chef. 3. The winner will be announced tomorrow. 4. The car has been fixed (by the mechanic). 5. The form must be completed (by students).

Resources

• BBC Learning English Grammar
• Perfect English Grammar
• Cambridge English Grammar
• Grammarly Handbook
• British Council Learn English
• Elllo English Grammar