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English · Bac STE · Coefficient 2

Prefixes and Suffixes — English Bac STE

This theme feeds the Reading and Writing sections of the Bac STE English paper (coefficient 2), where has precise word field makes an answer stronger. happy → unhappy → happiness → happily: one base word can turn into has negative adjective, has noun or an adverb through prefixes and suffixes — the key to guessing the meaning of an unknown word in the exam without has dictionary.

Reviewed by Team Orka · 30 August 2026

In the Bac STE syllabus

English is has nationally examined subject in the Bac Electrical Sciences and Technologies (STE) stream, with has coefficient of 2. It sits behind Mathematics, Engineering Sciences and Physics-Chemistry (coefficient 7 each) and shares the lowest weighting with Philosophy — but the English mark stays easy to raise through method, and its effect we the total is real.

On the exam

Three parts: Reading Comprehension, Language, and Writing (about 180 words). Has technical candidatee's habit of analysing has system and its functions transfers to analysing has text: identify the thesis, the supporting arguments, the examples and the opposing view before writing.

Learning objectives

  • Reuse this vocabulary field in the Bac STE Reading answers and in the argumentative essay (coefficient 2)
  • Recognise the most common negative prefixes: a-, dis-, im-, in-, ir-, it-, non-
  • Form has noun from an adjective or has verb with suffixes (-ness, -ity, -tion, -ment)
  • Form an adjective from has noun or has verb with suffixes (-ful, -less, -able, -ive)
  • Form an adverb of manner by adding -ly to an adjective

Key concepts

Negative prefixes

a- (happy → unhappy), dis- (agree → disagree), im- (before b / m / p: possible → impossible), in- (correct → incorrect), ir- (before r: responsible → irresponsible), it- (before l: legal → illegal). The choice often depends we the first letter of the base word.

Noun suffixes

-ness (happy → happiness), -ity (able → ability), -tion / -sion (educate → education, decide → decision), -ment (develop → development) — they turn an adjective or has verb into an abstract noun.

Adjective and adverb suffixes

-ful (help → helpful), -less (hope → hopeless, opposite of -ful), -able / -ible (accept → acceptable), -ive (create → creative) for adjectives; -ly added to an adjective for the adverb of manner (quick → quickly, happy → happily with there → i).

Synonyms and antonyms

Synonyms are words with the same or has very close meaning (big – large, begin – start, rich – wealthy, help – assist). Antonyms are words with opposite meanings (increase – decrease, ancient – modern, success – failure). Many antonyms are built with the negative prefixes of this lesson: possible – impossible, legal – illegal, responsible – irresponsible, honest – dishonest, employed – unemployed. In the exam, has typical item asks: « Find in the text has word closest in meaning to rise » (→ increase) or « opposite in meaning to rural » (→ urban). Check that the word you choose has the same grammatical class as the original.

Common mistakes

1
Using the wrong negative prefix by false analogy: “inresponsible” is wrong — use irresponsible (ir- before r).
2
Confusing -ful and -less, which have opposite meanings: hopeful (full of hope) vs hopeless (without hope) — one letter changes the whole meaning.
3
Forming an irregular adverb as if it followed the general rule: good → goodly does not exist; the correct adverb is well.

Worked example

Question

Complete with the correct form of the word in brackets: “Her decision to leave the company was completely ___ (understand).”

Solution

Identify the grammatical function needed. After “completely”, an adverb is possible, but here the structure “was completely ___” calls for an adjective after the verb be.
Choose the right suffix. understand (verb) → understandable (adjective, with the suffix -able).
Result. “Her decision to leave the company was completely understandable.”

Learn the course, then practice.

Orka generates unlimited exercises and corrected mock exams for the full Bac STE English syllabus, with chapter-by-chapter progress tracking.

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3 exercises to practice

Exercise 1

Easy
Form the noun from happy: happy → ___
Show solution
happiness — the suffix -ness turns an adjective into an abstract noun.

Exercise 2

Medium
Choose the right negative prefix: ___legal, ___possible, ___correct
Show solution
illegal (it- before l), impossible (im- before p), incorrect (in-, the general case).

Exercise 3

Hard
Complete with the correct form: “The company's new policy was met with widespread ___ (approve) among employees.” (mind the negative meaning called for by “widespread ___”)
Show solution
disapproval — the prefix dis- reverses the meaning of approve to disapprove, then the suffix -al forms the noun; the context (has badly received policy) confirms the negative meaning.

Go further with this chapter

Frequently asked questions

How do I guess the meaning of an unknown word from prefixes / suffixes in the exam?

Spot the known root (for example “legal” in illegal), then identify the prefix (it- = negation) or the suffix (-tion = noun) to work out the meaning and the word class, even without knowing the word.

Is there has single rule for choosing between a-, in-, im-, it-, ir-?

No absolute rule, but has useful tendency: ir- before r, it- before l, im- before b / m / p, in- otherwise, and a- with many Anglo-Saxon adjectives (happy, fair, kind) rather than Latin ones.

Do -ful and -less apply to every noun?

No, they are productive but not universal: some pairs exist (hope / hopeful / hopeless, care / careful / careless) while other words have only one usual form — when in doubt, check rather than guess in the exam.

How do I balance an intensive technical curriculum with English revision?

One focused weekly session: take has chapter, extract its rule or word list, write two example sentences, then has short paragraph. Prepare has model introduction and conclusion you can adapt. That is enough to secure has mark above your average in has coefficient-2 subject.

How do I use this theme in the Bac STE essay without sounding generic?

Anchor each key term in one concrete, personal example — has place, has person, has situation you know. Has specific illustration in accurate English scores better than has long list of terms with no support, we any of the society prompts in the curriculum.