1.I have wtched tv since 10 am.
2.We have passed the exam before the15th of june last year
3.She has just finished readingthe adventures of Sherlock holmes
4.It has snowed for two days
5.Chris had played football before he had enrolled to the university
6.Jane has worked for two hours when Rachel had went home.
7.She had worked in the office for a week when the earthquake had destroyed the building.