As (As I walked along the street/as I was hungry)

The conjunction 'as' is commonly used in English with two main meanings: 'while' (to show two actions happening at the same time) and 'because' (to give a reason). It often introduces a clause with its own subject and verb.

• 'As' meaning 'while' describes simultaneous actions: As I walked, I listened to a podcast.
• 'As' meaning 'because' explains a reason: As I was hungry, I stopped for lunch.
• The verb tenses in the 'as' clause usually match the time reference (past/present).

When the 'as' clause comes first, a comma often separates it from the main clause.

Decide whether 'as' links simultaneous actions (time) or gives a reason (cause). This changes how you interpret the sentence but not the structure of the clause.

• If 'as' = 'while': focus on two actions happening together. Use continuous or simple past as appropriate.
• If 'as' = 'because': the 'as' clause explains WHY something happened; often interchangeable with 'since' or 'because' in formal contexts.
• Punctuation: When the 'as' clause comes first, you usually add a comma: As I arrived, the meeting began.

If meaning is unclear, replace 'as' with 'while' or 'because' to test which sense fits.

Learners often make predictable errors with 'as'. Watch for these universal issues:

• Confusing 'as' with 'like': 'As' introduces a clause (subject + verb); 'like' is followed by a noun or pronoun.
• Using the wrong tense: ensure the tense in the 'as' clause matches the time reference (e.g., past continuous for ongoing past actions).
• Ambiguous meaning: using 'as' where the sentence could mean both 'while' and 'because'—rephrase if clarity is needed.
• Incorrect punctuation: forgetting the comma when the 'as' clause starts the sentence can make long sentences harder to read.

If in doubt, test the clause by replacing 'as' with 'while' or 'because' to see which meaning fits best.