Adverbs of Duration – For and Since
When we want to talk about for how long something happens or is the case, we generally use the prepositions for and since along with a determiner of time.
When we use for, we pair it with a word or words that specify a length of time; with since, on the other hand, we use specific points in time. Both usually occur at the end of the sentence, unless they are being followed by infinitive or prepositional phrases. And, as we’ve seen already, they can also be used at the beginning of the sentence to add emphasis.
Here are a few examples of each:
For
- “I have been running for three hours.”
- “They have been waiting for two months to be seen by a doctor.”
- “For 10 years, we’ve seen this country’s economy continue to decline.”
Since
- “Our computer systems have been having issues since last week.”
- “We have been looking since September for a place to live.”
- “Since we were kids, we’ve always dreamed of being astronauts.” (The phrase we were kids in this sentence might seem like it should be “the time when we were kids,” but because it is used with since, the shorter version is acceptable.)
In Proper Order
Remember, adverbs of time can be used to describe three different aspects: duration, frequency, and certain points in time (when). If we are using multiple adverbs of time in the same sentence, and if there is no special emphasis given to one aspect over another, then that is the order in which they generally appear.
Even if one of the three aspects is omitted, the other two still maintain their position in relation to each other. Here are some examples:
- “I went door to door for two hours every afternoon last year.”
- “He will be traveling for two years after college.”
- “The train runs hourly in the fall.”
If one aspect of time is being given particular emphasis in the sentence, then it generally comes later in the order. Let’s look at the first sentence arranged in a different order:
- “I went door to door every afternoon last year for two hours.”
As we can see, for two hours is given stronger emphasis than either every afternoon or last year.
Notice as well that each adverb of duration is made using for; we can’t use since
in the same way with multiple adverbs. For instance, we can see how the following would not make any sense:
✖ “She’s known him since high school each day this year.” (incorrect)
If we are using since to indicate duration along with other adverbs of time in the same sentence, then it must come after adverbs of frequency (or at the beginning of the sentence), and it can only be used with certain kinds of verbs.
For Example:
- “We’ve spoken to each other every day since high school.”
- “Since my operation, I’ve been getting stronger every day.”
- “He’s been feeling dizzy frequently since his car accident last spring.”
