Understanding the Uses of “Since” and “For” in English Grammar

In English, “since” and “for” are commonly used to express time duration, particularly in the present perfect and present perfect continuous tenses. However, their uses differ in meaning and function. Understanding their correct application is essential for fluency in English communication.

This blog post explores the differences, rules, and practical usage of “since” and “for” with detailed examples.

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1. Understanding “Since”

Definition:

“Since” is used to indicate a starting point in time. It refers to a specific moment when an action began and continues up to the present.

Usage Rules for “Since”:

1. Used with the Present Perfect or Present Perfect Continuous Tense

   • ✅ Correct: I have been living here since 2010.
   • ❌ Incorrect: I am living here since 2010. (Use “have been living”)

2. Follows a Specific Point in Time

   • ✅ Correct: She has been studying since morning.
   • ✅ Correct: We have known each other since high school.

3. Can Be Used with a Clause (Since + Subject + Verb)

   • ✅ Correct: I have been waiting since you left.
   • ✅ Correct: They have been happy since they got married.

Examples of “Since”:

Sentence	Explanation
I have been working since 9 AM.	The work started at 9 AM and is still going on.
She has been waiting for you since Monday.	The waiting started on Monday and continues.
We haven’t met since last year.	The last meeting was last year.

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2. Understanding “For”

Definition:

“For” is used to indicate a duration of time—how long an action has been happening.

Usage Rules for “For”:

1. Used with the Present Perfect or Present Perfect Continuous Tense

   • ✅ Correct: I have been living here for ten years.
   • ❌ Incorrect: I am living here for ten years. (Use “have been living”)

2. Follows a Duration of Time

   • ✅ Correct: She has been studying for three hours.
   • ✅ Correct: We have known each other for five years.

3. Can Be Used with Different Tenses

   • ✅ Correct (Present Perfect): I have known her for a long time.
   • ✅ Correct (Past Simple): He stayed in London for a month.
   • ✅ Correct (Future): She will be in Japan for two weeks.

Examples of “For”:

Sentence	Explanation
I have been working for eight hours.	The work has lasted for eight hours.
She has been waiting for 30 minutes.	The waiting has continued for 30 minutes.
We stayed in Paris for a week.	The stay lasted a week.

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3. Key Differences Between “Since” and “For”

Aspect	Since	For
Meaning	Refers to the starting point of an action.	Refers to the duration of an action.
Follows	A specific time (e.g., Monday, 2010, last week).	A period of time (e.g., two years, five hours).
Tense Usage	Present perfect, present perfect continuous.	Present perfect, present perfect continuous, past simple, future.
Examples	I have lived here since 2015.	I have lived here for 8 years.

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4. Common Mistakes and How to Avoid Them

1. Using “since” with a duration instead of a point in time

   • ❌ Wrong: I have lived here since five years.
   • ✅ Correct: I have lived here for five years.

2. Using “for” with a specific starting point

   • ❌ Wrong: She has been here for Monday.
   • ✅ Correct: She has been here since Monday.

3. Using “since” with simple present or past

   • ❌ Wrong: I work here since 2018.
   • ✅ Correct: I have worked here since 2018.

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5. Practice Exercises

Try filling in the blanks with “since” or “for”:

1. I have known him ___ childhood.
2. She has been waiting ___ two hours.
3. We have lived here ___ 2015.
4. He has been working in this company ___ a long time.
5. They have been friends ___ high school.

Answers:

1. since
2. for
3. since
4. for
5. since

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Conclusion

Understanding the difference between “since” and “for” is crucial for speaking and writing English correctly. “Since” is used for a specific starting point in time, while “for” is used for a duration. By practicing these rules, you can improve your fluency and avoid common mistakes.

Would you like more grammar tips? Let us know in the comments! 😊