12 English Grammar Rules Beginners Break (With Easy Fixes)

Priya Sharma

Priya Sharma writes English learning guides for ESL students. Pune-based language enthusiast.

Visual representation of the voice · not a photographic portrait

Quick answer: The grammar rules beginners break most are small ones used every day: adding -s after he/she/it, choosing a or an, using past simple for finished time, putting do/does in questions, and in/on/at for time. Learn these 12 rules with one clear example each and most of your everyday mistakes disappear.↗ Share on X

The English grammar rules that beginners break most are small ones you use every day: adding -s to verbs after he, she and it, choosing a or an, using the past simple for finished time, putting do/does in questions, and using in, on, at for time. Learn the 12 rules below, each with one wrong and one right example, and most of the mistakes people notice in your English will disappear.

You do not need to memorize a thick grammar book. You need the short list of rules that show up in almost every conversation.

Which grammar rules should you learn first?

READ ALSOPick the Right English Tense for Daily Life Easily →English Grammar Essentials: 10 Rules That Fix Most Mistakes →English Grammar Checklist: 10 Rules to Check Before Sending →

Not all rules are equal. Some mistakes only make you sound a little foreign. Others confuse the person listening. Start with the ones people hear every single day.

Now let's look at each rule in plain words.

Rule 1: Why add -s after he, she and it?

In the present simple (the tense for habits and facts), the verb changes only for he, she, it or one person or thing.

• I work. You work. We work. They work.
• He works. She works. My brother works. The shop opens at 9.

Watch the spelling:

• Verbs ending in -s, -sh, -ch, -x, -o take -es: watches, goes, fixes.
• Consonant + y becomes -ies: study → studies.
• "Have" becomes has: She has a car.

Quick test: if you can replace the subject with "he" or "she," the verb needs -s.

Rule 2: When do you use "a" and when "an"?

READ ALSOEnglish Grammar Rules to Learn First When Time Is Short →English Grammar Rules With Limited Time: The Essentials →The 12 English Mistakes That Make You Sound Like a Beginner →

The choice depends on the first sound, not the first letter.

• Use an before a vowel sound: an apple, an hour (the h is silent), an MBA ("em").
• Use a before a consonant sound: a car, a university ("you"), a one-way street ("won").

Also remember: use a/an when you mention something for the first time, and the when the listener already knows which one. "I bought a phone. The phone was cheap."

Rule 3: When do you use past simple, not present perfect?

This is a big one for speakers of many languages.

• Use past simple when you say *when* it happened, and that time is finished: yesterday, last week, in 2019, two hours ago. → *I saw him yesterday.*
• Use present perfect (have/has + past participle) when the time is not finished or not said: *I have seen that movie. She has lived here all her life.*

Simple trick: if your sentence has "ago," "yesterday" or "last," use the past simple. Never "have" with those words.

Rule 4: How do you make questions correctly?

English questions usually need a helper verb. For the present simple, the helper is do or does. For the past, it is did.

Notice: after does and did, the main verb goes back to its base form. Say "Does she like," not "Does she likes." Say "Did they call," not "Did they called."

Rule 5: How do "in, on, at" work for time?

Think of it as a pyramid from big to small:

1. in for long periods: in 2025, in July, in the summer, in the morning

2. on for days and dates: on Monday, on May 5, on my birthday

3. at for exact times: at 7 o'clock, at noon, at night, at the weekend (British English; Americans say "on the weekend")

Rule 6: Which nouns never take -s?

Some nouns are uncountable, which means you cannot count them one by one. They have no plural form. Common ones: advice, information, news, furniture, luggage, homework, money, bread, water, equipment.

• Wrong: *She gave me good advices.*
• Right: *She gave me good advice.* / *She gave me two pieces of advice.*

With uncountable nouns, use much and little. With countable nouns, use many and few. "How much money?" but "How many dollars?"

Rule 7: What is the difference between "few" and "a few"?

This small word changes the whole meaning.

• a few = some, a small number (positive). *I have a few friends here, so I am not lonely.*
• few = almost none (negative). *Few people came, so the party was quiet.*

The same logic works for uncountable nouns: a little (some) and little (almost none). *I have a little time* means you can help. *I have little time* means you probably cannot.

Rule 8: How do you stop mixing up its, your and there?

These words sound the same but mean different things.

Test: try saying the long form. If "it is" or "you are" fits, use the apostrophe.

Rule 9: Why is a double negative wrong?

In standard English, one negative word is enough. Two negatives cancel each other.

• Wrong: *I don't know nothing.* / *She didn't say nobody.*
• Right: *I don't know anything.* / *She didn't talk to anybody.*
• Also right: *I know nothing.* (one negative only)

After not, use any-words: anything, anybody, anywhere.

Rule 10: Where does the adjective go?

In English, the adjective (the describing word) goes before the noun and never takes -s.

• Wrong: *a car red*, *two reds cars*
• Right: *a red car*, *two red cars*

When you use several adjectives, a common order is: opinion, size, age, color, material. *A nice big old red wooden table.* In real speech, two adjectives is usually plenty.

Rule 11: How do you compare things correctly?

• Short words (one syllable) add -er / -est: big → bigger → biggest.
• Long words use more / most: expensive → more expensive → most expensive.
• Never use both: not "more bigger," not "most easiest."
• Irregular: good → better → best; bad → worse → worst.
• Use than after the comparative: *My car is older than yours.*

Rule 12: When do you use "since" and when "for"?

Both talk about time up to now, so they usually go with the present perfect.

• since + starting point: since Monday, since 2020, since I was a child.
• for + length of time: for two weeks, for ten years, for a long time.

Wrong: *I live here since 2020.*

Right: *I have lived here since 2020.* / *I have lived here for five years.*

How do you practice so the rules stick?

Reading rules is not enough. Your brain needs to catch the mistake many times before the right form feels natural. Try this short routine:

1. Pick two rules per week. Not all twelve. Start with rules 1 and 3.

2. Write five sentences about your own life using those rules each day. Real sentences stick better than textbook ones.

3. Read them out loud. Speaking builds the habit faster than silent reading.

4. Record yourself for one minute talking about your day. Listen back and count the mistakes on your two rules only.

5. Next week, add two new rules and keep reviewing the old ones.

After six weeks, you will have gone through all twelve.

Your next step

Look at the table at the top of this page and choose the two rules you break most often. Write five true sentences about yesterday and today using them, for example: "Yesterday I called my sister. She works at a hospital." Read them out loud once. Tomorrow, do five more. That is the whole plan for this week.

FAQ

What is the most common English grammar mistake?

Forgetting the -s on verbs after he, she or it in the present simple, as in 'She work here' instead of 'She works here.' It is easy to fix once you notice it, because the rule has very few exceptions.

When do I use 'since' and when do I use 'for'?

Use 'since' with a starting point (since Monday, since 2020) and 'for' with a length of time (for three days, for ten years). Both usually go with the present perfect: 'I have lived here since 2020.'

How long does it take to stop making these mistakes?

It depends on how often you practice. Most learners notice real progress after a few weeks of short daily practice focused on one or two rules at a time, instead of studying all the rules at once.