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A Comprehensive Guide to "as...as" Structure in English

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This article provides a comprehensive overview of the "as...as" structure in English, covering its basic usage, sentence positions, scope of modification, and special use cases.

1. Basic Concepts and Structure

The "as...as" structure is used to express equality between two things in terms of a particular characteristic or degree. The basic complete sentence structure can be summarized as:

Subject (S) + Linking/Action Verb (V) + as + Adjective/Adverb (adj./adv.) + as + Object of Comparison

Or more simply:

S + V + as + adj./adv. + as + Noun/Pronoun/Phrase

Examples:

  • She is as tall as her brother. Analysis:

    • Subject (S): She
    • Linking Verb (V): is
    • Adjective: tall
    • Object of Comparison: her brother
    • Meaning: The height of the subject equals that of her brother.

  • He runs as fast as a cheetah. Analysis:

    • Subject (S): He
    • Action Verb (V): runs
    • Adverb: fast
    • Object of Comparison: a cheetah
    • Meaning: The speed of his running equals that of a cheetah.

Through this structure, we can express equality in various characteristics or degrees such as "height, speed, size, intelligence."

2. Detailed Usage

2.1 After Linking Verbs

When "as...as" follows linking verbs (such as be, look, seem, feel, sound, etc.), it primarily describes the equality of a subject's attributes.

Examples:

  • She is as intelligent as her mother.
    • This indicates equal intelligence between the subject and her mother.
  • The cake smells as good as it looks.
    • This compares the cake's smell to its appearance.

2.2 After Action Verbs

When "as...as" follows action verbs with an adjective or adverb, it describes the equality in the degree of the action.

Examples:

  • She runs as fast as her friend.
    • This compares the speed of running between two people.
  • He works as hard as his brother.
    • This compares the degree of effort in working.

2.3 After Nouns (Attributive Function)

The "as...as" structure can also modify nouns, functioning as an attribute in noun phrases. In this case, it directly modifies the noun to describe its attributes or requirements.

Examples:

  • I need a car as fast as yours.

    • Here, "as fast as yours" is an attributive phrase modifying "a car."
    • It means we're looking for a car with speed equal to yours.

  • We are looking for a solution as simple as possible.

    • "as simple as possible" modifies "a solution," indicating we want the simplest possible solution.

  • I want something as big as an elephant.

    • "as big as an elephant" modifies "something," describing the desired size.

In this usage, the "as...as" phrase forms a noun phrase with the noun (such as object phrases or subject modifiers) and isn't just used as a predicate.

3. Negative Form

The negative form "not as/so ... as" expresses inequality or inferiority.

Examples:

  • This movie is not as interesting as the last one.
    • This indicates the current movie is less interesting than the previous one.
  • I'm not as good at math as you.
    • This expresses that the speaker's math ability is inferior to the listener's.

4. Common Idioms and Fixed Expressions

English has many fixed "as...as" idioms that vividly describe degrees of qualities:

  • as light as a feather
    • Describes something extremely light
  • as busy as a bee
    • Describes someone very busy
  • as cold as ice
    • Describes extreme coldness
  • as poor as a church mouse
    • Describes extreme poverty

These expressions help make language more vivid and expressive.

5. Key Points Summary

  1. Comparison Objects Required:
    The "as...as" structure requires two elements: the subject being described and the object of comparison.

  2. Position Determines Modification:

    • After linking verbs: describes subject attributes or states
    • After action verbs: describes degree of action
    • After nouns: functions as an attribute describing characteristics

  3. Positive and Negative Forms:
    The positive form "as...as" expresses equality, while the negative form "not as...as" expresses inequality or inferiority.

  4. Idioms and Fixed Expressions:
    Learning common "as...as" idioms enriches language expression.