Use the preposition "since" when referring back to the beginning of something in time.

 1. I haven’t spoken on the phone since yesterday.

(This preposition is often used with negative present perfect tense verbs.)

 2. We haven’t seen them since the wedding.
 3. She has been learning English since late last year.
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 4. He has lived in the United States since 2005.
 5. The temperatures where we live have been noticeably higher since the start of this century.
 6. Since the dawn of civilization, human beings have invented many different kinds of weapons.
7. The world seems to have changed a lot since 9/11.


* The preposition "since" is often used with the present perfect tense.

* If you use "since" with a subject and a verb, it becomes part of an adverb clause:

I haven’t seen her since she was a little girl.