The Distinction Between AS and LIKE

The distinction between "as" and "like" is one of the most common hurdles in English grammar. While they both function as tools for comparison, the difference lies in their grammatical "weight"—specifically, what kind of words follow them.

​Here is a guide to mastering the nuances between the two.

​1. The Golden Rule: Structure

​The easiest way to decide which word to use is to look at what follows it.

​Use "Like" with Nouns or Pronouns

​Think of like as a preposition. It is used to compare two things based on appearance or behavior. It is followed by a noun, a pronoun, or a gerund (-ing word), but never a full clause (subject + verb).

• ​Example: "She sings like an angel." (Noun)

• ​Example: "He runs like me." (Pronoun)

​Use "As" with Clauses

​Think of as as a conjunction. It is used when the comparison includes a subject and a verb.

• ​Example: "She sings as an angel sings." (Subject + Verb)
• ​Example: "Do as I say, not as I do." (Subject + Verb)

​2. Comparing Function vs. Appearance

​Sometimes, the choice between "as" and "like" changes the entire meaning of your sentence.

Word	Meaning	Example
As	In the role of / Capacity	"I am speaking as your doctor." (I am a doctor.)
Like	Similar to / Comparison	"I am speaking to you like a doctor." (I am not your doctor, but I'm acting like one.)

3. Common Phrases and Idioms

​While the rules above cover 90% of cases, English has a few specific patterns you should know:

• ​Such as (Examples): Use "such as" instead of "like" when introducing a list of examples.
  • ​Correction: "I enjoy citrus fruits such as oranges and lemons."
• ​As if / As though: Use these to describe an imagined or hypothetical situation.
  • ​Example: "He looked as if he had seen a ghost."
• ​As... as: Used for comparisons of equality.
  • ​Example: "The water is as cold as ice."

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  ​4. The "Informal" Trap

  ​In casual conversation, you will often hear people use like where as should technically go.

  • ​Casual: "Nobody knows him like I do."
  • ​Formal: "Nobody knows him as I do."

  ​While using "like" as a conjunction is becoming more acceptable in spoken English, it is best to stick to "as" in professional or academic writing to ensure clarity and precision.