Prefixes are letters added to the beginning of a word to change its meaning. In this lesson, you will learn how common prefixes like un-, mis-, dis-, and re- help you express precise meanings in your communication.
Examples
Example 1
IncorrectThe instructions were clear, so everyone understood them.
BetterThe instructions were unclear, so not everyone understood them.
'Unclear' uses the prefix 'un-' to indicate the opposite of 'clear.'
Example 2
IncorrectHe wrote the report after receiving new data.
BetterHe rewrote the report after receiving new data.
'Rewrite' uses the prefix 're-' to indicate doing the action again.
How It Works
Meaning
Prefixes are groups of letters added to the beginning of a word to alter its meaning. They can indicate negation, repetition, or an incorrect action, among other things. For example, adding 'un-' to 'happy' creates 'unhappy,' indicating the opposite meaning. At the B2 level, understanding prefixes helps you expand your vocabulary and express nuanced meanings more precisely.
Use it when
- You need to express a negative or opposite meaning, such as 'unhappy' or 'disagree.'
- You want to indicate repetition of an action, like 'rewrite' or 'redo.'
- You need to convey an incorrect action, such as 'misunderstand.'
- In formal writing or speaking, where precise word choice is crucial.
- When preparing for exams like IELTS or CELPIP that test vocabulary range.
See it
Quick rules
- Use 'un-', 'in-', 'dis-' for negation or opposite meanings.
- Use 're-' to indicate repetition of an action.
- Ensure the prefixed word is commonly used in English.
- Check that the new word fits the context of your sentence.
- Avoid inventing new words; rely on established vocabulary.
Common Mistakes
Common problem 1
using the base word where the sentence needs a prefix meaning
WeakThe manager asked us to check the data again, so we had to view the file before submission.
StrongThe manager asked us to check the data again, so we had to review the file before submission.
Fix: Use 're-' to indicate repetition of an action.
Common problem 2
using a positive base form when the context needs a negative prefix
WeakThe online form is possible to complete without an ID.
StrongThe online form is impossible to complete without an ID.
Fix: Use 'im-' to negate the base meaning.
Common problem 3
forgetting re- when the action is repeated
WeakPlease write your answer after checking the teacher comments.
StrongPlease rewrite your answer after checking the teacher comments.
Fix: Use 're-' when the action clearly means to do again.
Practice Lab
Practice
First notice the right form. Then build it yourself. Then fix it in a full sentence.
Score: 0/3
Read for meaning first. If the meaning changes, the grammar usually has to change too.
1. Quick pick
Choose the sentence that correctly uses a prefix.
2. Build it
Put this Prefixes sentence in the correct order.
Tap a chunk to move it down. Tap it again to send it back.
3. Final sort
Mark each sentence as correct or needing a fix.
The instructions were unclear, so not everyone understood them.
The instructions were clear, so not everyone understood them.
He rewrote the report after receiving new data.
He wrote the report after receiving new data.
Why It Matters
🎯 Why it matters: Understanding prefixes allows you to modify words to express exact meanings efficiently, making your English more precise and effective for tasks in IELTS and CELPIP.
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