Content
Expression of length and/or continuity of actions
For and Since are prepositions used to express the length and continuity of actions started in the past and continuing in the present. They are different because the first one specifies the time length of the action, while the second one defines the moment when the action began.
Look the following image to understand the difference between these two prepositions and see how you can use them to make sentences. If you move the mouse over the red blinking spots, you will find some example phrases that you can use in each case.