Grammar Exercise: For/Since Error

1. They have been going out together for last February.
    Correct
    Not Correct

2. According to this label, the document hasn't been updated since two years.
    Correct
    Not Correct

3. Since the summer, the town's population has grown by nearly a quarter.
    Correct
    Not Correct

4. Due to the accident, the street has been closed since just after nine o'clock.
    Correct
    Not Correct

5. The oldest newspaper in town, The Sentinel, has been published continuously since 120 years ago.
    Correct
    Not Correct

6. I've been on a diet since such a long time, it's so depressing!
    Correct
    Not Correct

7. The whole family spent August in Chicago. They've done that every year for ages.
    Correct
    Not Correct

8. For the longest time, I've wanted to do that and now I have!
    Correct
    Not Correct