present perfect "since and for"

For six years, for a week, for a month, for hours, for two hours.
Example:
I have worked here for five years.

​​Since
"A period of time"

"A point in time"

Since this morning, since last week, since yesterday, since I was a child, since Wednesday, since 2 o'clock
Example:
We have taught at this school since 1965.

​​For

Watch the next videos an take notes in order to have a better understanding of the topic. Don't forget to highlight main key points, they are very useful.