subject + be + as + adjective + as + noun/pronounUse this for equal comparison with adjectives. The adjective stays in its base form.
As...As Comparison
A2Use as...as for equal comparison and not as...as for lower degree. Keep the adjective or adverb in its base form.
What you'll learn
- Compare two things as equal with as + adjective + as.
- Show lower degree with not as + adjective + as.
- Compare actions with as + adverb + as.
- Choose the right pattern for equal meaning or lower meaning.
- Keep the word in base form after as, never comparative.
Structure
subject + be + not + as + adjective + as + noun/pronounUse this when the first person or thing has less of the quality than the second one.
subject + main verb + as + adverb + as + noun/pronounUse this to compare actions. The adverb stays in its base form too.
Build a sentence
Subject
Quality
Compared with
MariaisasfastasLisa
Maria is as fast as Lisa.
Keep fast in base form, not *faster*.
When to use
Equal qualities
Compare two people or things when they are equal in one quality: age, height, speed, price, or difficulty.
Lower degree
Show that one side has less of a quality than the other: not as cheap as, not as easy as, not as quickly as.
Actions
Use adverbs to compare how actions happen: runs as fast as, speaks as clearly as, works as hard as.
Markers
as tall asas fast asas expensive asnot as easy asas quickly asnot as well as
In contrast
vs comparative-adjectives
as...as shows equality or lower degree with not as...as. Comparative adjectives show difference directly: taller than, cheaper than.
vs comparison-clauses
This rule focuses on the fixed comparison frame as...as. Longer comparison clauses add extra words after it, but the core frame stays the same.
Common mistakes
Wrong
Tom is as tall his brother.
Correct
Tom is as tall as his brother.
The pattern has two as words: one before the adjective and one after it.
Wrong
Maria is as taller as Lisa.
Correct
Maria is as tall as Lisa.
After as, use the base adjective, not the comparative form.
Wrong
This bag is not as heavier as that one.
Correct
This bag is not as heavy as that one.
Do not mix not as...as with a comparative adjective. Use the base form only.
Wrong
This test is as more difficult as the last one.
Correct
This test is as difficult as the last one.
The as...as pattern does not take more. Keep the adjective in base form.
Wrong
Tom drives as careful as Maria.
Correct
Tom drives as carefully as Maria.
When you compare actions, use an adverb, not an adjective.
Common misconceptions
❝ One as is enough because the meaning is already clear. ❞
The fixed pattern needs two as words: as tall as, as fast as, as expensive as.
❝ Stronger comparison needs a comparative word inside the pattern. ❞
Inside as...as and not as...as, use the base adjective or adverb only.
Skills in this rule (6)
AS_ADJECTIVE_ASw5Use as + adjective + as for equal comparison
Use this pattern when two people or things are equal in one quality. Put the adjective between the two as words.
NOT_AS_ADJECTIVE_ASw5Use not as + adjective + as for lower degree
Use this pattern when one person or thing has less of a quality than the other. Keep the adjective in its base form after not as.
AS_ADVERB_ASw4Use as + adverb + as to compare actions
Use this pattern to compare how two actions happen. Put the adverb between the two as words: runs as fast as, speaks as clearly as.
CHOOSE_EQUAL_OR_LOWERw4Choose between as...as and not as...as
Use as...as for equality and not as...as when one side has less of the quality. Read the meaning first, then choose the pattern.
PICK_COMPARISON_CONTEXTSw3Recognize contexts for equal and unequal comparison
This pattern appears when you compare size, speed, price, difficulty, age, and similar qualities. Signal words often name two people or things directly.
KEEP_BASE_FORM_AFTER_ASw5Keep the adjective or adverb in its base form after as
Do not use -er, more, or the most inside this pattern. After as, use the plain adjective or adverb form.