The as 〜 as structure compares two things and expresses that they are at the same level: “as ... as.” This is called a “positive comparison” or “equal comparison.”
Basic Rules
The form is “as + the positive form of an adjective/adverb + as the comparison.” The adjective or adverb stays in its original form (the positive degree). It means “A is as ... as B.”
The negative form “not as 〜 as / not so 〜 as” means “A is not as ... as B.” This useful form expresses the same meaning as the comparative “A is smaller than B” from a different perspective.
To express “〜 times,” put a multiplier before the expression, as in “twice as 〜 as” and “three times as 〜 as.”
Tom is as tall as Ken. (Tom is as tall as Ken.)
She can run as fast as her brother. (She can run as fast as her brother.)
This book is not as interesting as that one. (This book is not as interesting as that one.)
This bag is twice as expensive as mine. (This bag is twice as expensive as mine.)
Points to Note
① The adjective or adverb inside “as 〜 as” must be in the positive degree. Do not use the comparative (× as taller as → ○ as tall as).
② Relationship between not as 〜 as and the comparative: “A is not as tall as B.” = “A is shorter than B.” = “B is taller than A.” One situation can be expressed in three ways.
③ With adverbs: can run fast → as fast as / studies hard → as hard as. Adverbs that modify verbs can also be used in the same as 〜 as structure.
④ Multiplier + as 〜 as: half as 〜 as, twice as 〜 as, three times as 〜 as, four times as 〜 as.
- as + positive degree + as + comparison = “as ... as”
- not as 〜 as = “not as ... as”
- Adverbs can also be used with as 〜 as.
- Multipliers: twice / three times + as 〜 as
- The positive degree does not change form.
Practice
- Write “My dog is as cute as your dog” in English.
- Using not as 〜 as, write “This problem is not as difficult as that one.”
- Write “She can run three times as fast as I can” in English.