If you’re learning English, check your sentences for articles, verb tenses, prepositions, subject–verb agreement, and helping verbs. The examples below show what to change and why. Start with the pattern you see most often in your own writing or speaking.
Quick reference
| Pattern | Instead of | Try | What to check |
|---|---|---|---|
| Articles | I borrowed dictionary for class. | I borrowed a dictionary for class. | Here, dictionary means one book. Use a when the listener doesn’t yet know which one. |
| Tense | I have enrolled last week. | I enrolled last week. | Use the simple past for an event at a finished past time. |
| Prepositions | We meet in Monday. | We meet on Monday. | Use on with days and dates. |
| Subject–verb agreement | The list of classes are online. | The list of classes is online. | The subject is built around list, which is singular. |
| Helping verbs | Does the library offers evening classes? | Does the library offer evening classes? | After does, use the base form of the main verb. |
1. When to use a, an, the, or no article
Use a or an with a singular countable noun when the listener doesn’t need to know exactly which one you mean. Use the when the listener can identify the person or thing from context. Watch how the article changes in the second sentence.
I picked up a workbook at the library. The workbook has an answer key.
You can also use the on first mention when the context identifies it. If you’re both standing in a classroom and there’s one door, Could you close the door? makes sense immediately.
Choose a or an by the next sound, including the first sound of any adjective. Use a in a useful exercise because useful starts with a “y” sound. Use an in an honest answer because the h in honest is silent.
When you mean a category in general, plural and uncountable nouns often take no article.
| Meaning | Example |
|---|---|
| Plural things in general | Workbooks can help you practice between classes. |
| An identifiable set of things | The workbooks on the front table are free. |
| Something uncountable in general | Feedback helps me spot patterns. |
| Something uncountable with a clear reference | The feedback on my first draft helped me revise it. |
A singular countable noun usually needs an article or another word that identifies it, such as my or this. Compare a workbook, the workbook, and my workbook. British Council article guide · More on article usage
2. How verb tense and aspect change meaning
Tense helps locate a situation in time. Aspect helps show how you see it, for example as ongoing or as connected to a later point in time. Compare these four ways to talk about studying.
| What you mean | Form | Example |
|---|---|---|
| A regular routine | Simple present | I study on Mondays. |
| An activity in progress now | Present continuous | I am studying right now. |
| An event at a finished past time | Simple past | I studied yesterday. |
| A past event with a result that matters now | Present perfect | I have finished the worksheet. I can hand it in now. |
The present perfect also describes a situation that began in the past and continues now. In I’ve lived here since March, March is the starting point. In I’ve lived here for six months, six months is the duration. Both sentences tell you that I still live here.
A change of time can call for a change of tense. In I worked during the day last year, and now I work evenings, the shift tells the reader exactly what changed. British Council present perfect guide · More examples of English tenses
3. How to choose in, on, or at
| Preposition | Time | Place |
|---|---|---|
| in | Months, years, and longer periods. The course starts in March. | Inside a space or area. We’re in the classroom. |
| on | Days and dates. We meet on Monday. | A surface. The sign-up sheet is on the table. |
| at | Clock times and points in the day. Class starts at 6 p.m. | A place you treat as a point or meeting spot. Meet me at the library. |
The same location can take different prepositions depending on what you mean. I’m at the library gives your location. I’m in the library makes clear that you’re inside. For movement, I walked to the library gives your destination. I walked into the library says you entered it. Cambridge’s place examples · More prepositions of time and place
Other prepositions belong to familiar expressions. Learn interested in and good at as pairs, then use each in a sentence of your own.
4. How to check subject–verb agreement
In the simple present, most verbs add -s or -es with he, she, it, or a singular noun. Compare The teacher checks our work and The teachers check our work. With be, compare the teacher is and the teachers are.
When a phrase comes between the subject and the verb, read the sentence once without it. In The box of pencils is on the desk, set aside of pencils. The sentence is still The box is on the desk. The verb agrees with box. Purdue OWL’s agreement guidance · More on subject–verb agreement
Group nouns such as team can follow different conventions. The team is ready presents the team as a unit. British English also allows forms such as The team are getting their bags, with the members in mind. The team members are getting their bags works across varieties. Cambridge on collective nouns
5. Helping verbs in questions and negatives
When a statement already has a helping verb such as is, has, or can, put the first helping verb before the subject to make a yes-or-no question. With an ordinary verb in the simple present or past, use do, does, or did and put the main verb in its base form.
| Statement | Question | Negative |
|---|---|---|
| The teacher posts notes. | Does the teacher post notes? | The teacher doesn’t post notes. |
| You brought a pen. | Did you bring a pen? | You didn’t bring a pen. |
| Lina is taking notes. | Is Lina taking notes? | Lina isn’t taking notes. |
| You have finished. | Have you finished? | You haven’t finished. |
| We can sit here. | Can we sit here? | We can’t sit here. |
Words such as can, might, and should are modal verbs. They help express meanings such as ability, permission, possibility, and advice. A core modal takes a base-form verb, as in You might need a pencil or You should bring a notebook. Cambridge on yes-or-no questions · More on modal verbs
Practice editing a message about an evening class
Imagine you’re telling a classmate about a workbook they haven’t heard about. Choose the words that complete the message.
- I got ___ workbook for class. (a / the)
- ___ workbook has exercises and an answer key. (A / The)
- Class starts ___ 6 p.m. ___ Thursday. (at / in / on)
- The list of supplies ___ on the last page. (is / are)
- I ___ the registration form yesterday. (sent / have sent)
- Does the instructor ___ extra copies? (have / has)
Check your answers and explanations
- A workbook. This is the first mention and the reader doesn’t yet know which one it is.
- The workbook. The reader can now identify it as the one mentioned in sentence 1.
- At 6 p.m. on Thursday. Use at for a clock time and on for a day.
- Is. The verb agrees with list, which is singular. The phrase of supplies describes the list.
- Sent. Yesterday places the event in a finished past time, so use the simple past.
- Have. After does, use the base form of the main verb.
Keep practicing with one pattern at a time
Find a pattern and use it
Pick one pattern to practice for a week. Find an example in something you actually read, such as a class notice or an email. Write two sentences of your own, then try using the pattern out loud. For prepositions, you might ask a conversation partner where and when to meet, then write a message confirming the plan. Mark the day and time on a calendar to see where each preposition belongs.
Ask for focused feedback
If someone spots an error, ask them to point to the words to check. Try the correction yourself and explain the choice. Save your first and corrected sentences so you can see which patterns are getting easier.
Find practice at your level
For practice with feedback, choose a topic and level in British Council LearnEnglish grammar exercises. If you prefer a workbook, look for a worked example and an answer key you can check on your own.
Set a goal you can check
Aim to write three messages with days and times this week. Reread them and check each use of on and at. When you can explain your choices, pick another pattern from the table.
