You’ve finished your draft. Now you’re checking the English—and wondering whether you’ve missed anything.
If English is an additional language for you, small grammar choices can take a surprising amount of time. Does that noun need the? Should the verb be singular or plural? Which preposition belongs here?
These twenty examples will help you spot common problems in academic writing. Each one includes a correction and a short explanation you can apply to your own draft.
You don’t have to check everything at once. Start with the mistakes you tend to make most often.
1. Letting a nearby noun confuse subject–verb agreement
Before:
“The results of the experiment shows a clear pattern.”
After:
“The results of the experiment show a clear pattern.”
Why it works:
The subject is “results”, which is plural. “Experiment” is closer to the verb, but it does not control the agreement.
Try this:
Find the main noun in the subject before choosing the verb.
2. Using a plural verb after “each”
Before:
“Each participant were given a questionnaire.”
After:
“Each participant was given a questionnaire.”
Why it works:
“Each participant” refers to people individually and takes a singular verb.
The same applies to “each student”, “each response”, and “each group”.
3. Changing tense halfway through a completed action
Before:
“We collected the data and analyse the responses.”
After:
“We collected the data and analysed the responses.”
Why it works:
Both actions happened in the past.
You can use different tenses within a paragraph when the meaning requires them. The problem is an unexplained change in time.
4. Using the present perfect with a finished past date
Before:
“The researchers have conducted the survey in 2024.”
After:
“The researchers conducted the survey in 2024.”
Why it works:
“In 2024” identifies a finished time in the past, so the past simple fits.
Without a finished past date, “The researchers have conducted several surveys” may be appropriate.
5. Leaving out an article before a singular count noun
Before:
“We developed questionnaire to measure satisfaction.”
After:
“We developed a questionnaire to measure satisfaction.”
Why it works:
A singular count noun such as “questionnaire” usually needs an article or another word such as “this” or “our”.
Here, “a” introduces the questionnaire.
6. Choosing “a” or “an” by spelling instead of sound
Before:
“The study took place at an university.”
After:
“The study took place at a university.”
Why it works:
“University” begins with a consonant sound, like the beginning of “you”.
Choose by sound: a university, an hour, an MRI scan.
7. Adding “the” when making a general statement
Before:
“The academic writing requires careful revision.”
After:
“Academic writing requires careful revision.”
Why it works:
This sentence refers to academic writing generally.
Use “the” when you mean something specific: “The academic writing in this sample contained several errors.”
8. Making an uncountable noun plural
Before:
“The interviews provided useful informations.”
After:
“The interviews provided useful information.”
Why it works:
“Information” is normally uncountable in English. So are “advice” and “evidence”.
If you need to count individual items, you can write “three pieces of information”.
9. Using “less” with a plural count noun
Before:
“Less participants completed the second survey.”
After:
“Fewer participants completed the second survey.”
Why it works:
Use “fewer” with things you can count: participants, responses, and errors.
Use “less” with amounts: less time, less information, and less effort.
10. Using the wrong preposition
Before:
“The findings are consistent to previous research.”
After:
“The findings are consistent with previous research.”
Why it works:
Some words regularly occur with particular prepositions.
Useful combinations include consistent with, associated with, dependent on, and an increase in.
Try this:
Learn the whole phrase rather than the preposition on its own.
11. Putting a verb in the wrong form after a preposition
Before:
“Participants were interested in join the programme.”
After:
“Participants were interested in joining the programme.”
Why it works:
After a preposition such as “in”, a verb normally takes the -ing form.
Other examples include “before submitting” and “without changing”.
12. Using the wrong form after a modal verb
Before:
“These factors may affects the results.”
After:
“These factors may affect the results.”
Why it works:
Use the base form of the verb after “may”, “might”, “can”, “could”, “should”, and “must”.
Write “may affect”, not “may affects” or “may to affect”.
13. Using an adjective when you need an adverb
Before:
“The two groups responded different.”
After:
“The two groups responded differently.”
Why it works:
“Differently” describes how the groups responded, so you need an adverb.
Compare “different responses”, where the adjective describes a noun.
14. Confusing a noun with a verb
Before:
“We conducted a detailed analyse of the responses.”
After:
“We conducted a detailed analysis of the responses.”
Why it works:
“Analysis” is the noun. “Analyse” is the verb in British English; American English uses “analyze”.
You could also write: “We analysed the responses in detail.”
15. Leaving a sentence unfinished
Before:
“Although the sample was small.”
After:
“Although the sample was small, it included participants from five departments.”
Why it works:
“Although” introduces a dependent clause. The reader still needs the main part of the sentence.
Read sentences beginning with “although”, “because”, or “whereas” carefully. Have you completed the thought?
16. Joining two complete sentences with only a comma
Before:
“The sample was small, the estimates were uncertain.”
After:
“The sample was small, and the estimates were uncertain.”
Why it works:
These are two independent clauses. A comma alone does not normally join them.
You can add a conjunction, use a semicolon, or write two sentences.
17. Using both “although” and “but” for the same connection
Before:
“Although attendance increased, but satisfaction remained unchanged.”
After:
“Although attendance increased, satisfaction remained unchanged.”
Why it works:
“Although” already introduces the contrast. You do not need “but” as well.
Another correct version is: “Attendance increased, but satisfaction remained unchanged.”
18. Mixing grammatical forms in a list
Before:
“The aims were to measure attendance, comparing outcomes, and the identification of barriers.”
After:
“The aims were to measure attendance, compare outcomes, and identify barriers.”
Why it works:
The three aims now follow the same pattern: measure, compare, and identify.
Try this:
Read each item with the opening words: “The aims were to…” Does every item fit?
19. Leaving the person doing an action unclear
Before:
“Using a questionnaire, satisfaction was measured.”
After:
“We measured satisfaction using a questionnaire.”
Why it works:
The opening phrase needs a clear connection to whoever used the questionnaire. Satisfaction itself did not use it.
If “we” is unsuitable for your paper, write: “The researchers measured satisfaction using a questionnaire.”
20. Putting an apostrophe in a simple plural
Before:
“Twenty participant’s completed the survey.”
After:
“Twenty participants completed the survey.”
Why it works:
A simple plural does not need an apostrophe.
Use an apostrophe for possession:
- The participant’s response: one participant
- The participants’ responses: more than one participant
How to use these examples on your own paper
Choose one paragraph and check it in three short passes.
First, check the verbs. Find the subjects, check agreement, and make sure the tenses match the time you mean.
Next, check the nouns and small words. Look at articles, plurals, pronouns, and prepositions.
Finally, check sentence structure. Look for unfinished sentences, comma splices, and lists with mixed forms.
After making changes, read the paragraph again. Your grammar may be better, but have you kept the same meaning?
You don’t need to memorise all twenty rules today. Keep a short list of the mistakes you find in your own drafts. That list will tell you where to focus next time.
Want a checklist beside you while you edit?
Download the free Academic English Proofreading Checklist for 25 checks with examples to help you review your draft before sharing or submitting it.
Marlene
Better English Writing