How to Teach For vs. Since

"For" and "since" are common English words that are used to talk about time and duration. The difference between them is subtle, so students may be confused about which to use.

In addition, both also work as conjunctions to explain why something is the way it is. While "because" is usually used for giving reasons, "for" and "since" have differences in nuance that can affect how a statement sounds. We'll take a look at all of these uses and provide tips on how to teach them to your students.

Expressing periods of time

The prepositions "since" and "for" are used to express periods of time. Students may have seen advertisements for classic brands with "since" written together with the year the business started, as in "Since 1930." Here are some other common examples:

• since Monday
• since last year
• since then
• since it began
• since childhood
• since we last met

As shown here, "since" is combined with a specific point in the past to express the start of a period of time.

On the other hand, "for" is used in combination with a length of time to express duration, or how long something has existed or has been happening.

• for 20 years
• for a while
• for a long time
• for one hour
• for decades
• for a few months

So "since" focuses on when a period started, while "for" focuses on the period in total. To help students get a better understanding of the difference, you can ask them about the two answers to this "how long" question.

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The first response refers to the starting point only, but the second expresses the duration of time, from the start until the present.

Because it refers to a starting point, "since" is used in the perfect tense.

"For," however, can be used to talk about any time. Try asking your student if they can change the previous example to refer to a past, present or future situation. 

Explaining a reason or cause

It's common to use "because" when giving a reason, and it can be used at the beginning or in the middle of a sentence. "For" and "since" can be used in the same way.

When used at the beginning of a sentence, the reason is separated from the result with a comma.

Explaining reasons using “since”

Although it can go at the beginning or in the middle of a sentence, "because" is often used in the middle in daily conversations. "Since," however, is common in both positions. It also sounds a little more casual than "because."

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Explaining reasons using “for”

"For" can be used just like the other two, but it is much more formal.

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Students should know that this usage is very old-fashioned. They may read it in a classic novel or hear it in a theater play, but they will probably never hear "for" used this way in a normal conversation. However, it can be useful to know, even if they don't have an opportunity to use it themselves!

Practice makes perfect

Both "for" and "since" are common English words that are often used in similar situations, so it can be easy for students to confuse them. Using the examples we've provided here should help them to see the differences between the two clearly.

Once you feel they understand the unique points of both words, give them a chance to practice by doing a short interview during the lesson. Ask them questions like how long they've been studying English, how long they've been doing their favorite hobby, how long they plan to study overseas, etc., and ask them to answer with both "for" and "since" sentences (if appropriate). 

You can also quiz them by giving them a "since" statement and asking them to rephrase it as a "for" statement.

This will help to strongly establish the different usages in their minds, and they will be more prepared to use and understand these important words in real-life situations.