EX15: Fill in the blanks with "since" or "for".
1. Mark has used the laptop __________ three hours ______________  10 o'clock.
2. How many times have you read the book ________________ you bought it?
3. Mary hasn't eaten fish __________________ Thursday.
4. We've known each other __________________ ages.
5. My sister has owned the fashion shop _________________ 3 years.
6. It's three years _________________ Trang started learning English.
7. Peter and Linda have been married ______________________ a year.
8. She has been to Paris ______________________ a week.
9. He has stayed here _______________________ three days.
10. I have worked as a teacher ___________________ 2018.