Complete the sentences with any appropriate time expressions .
1.I have had this book since ......... .
2.I have had this book for ......... .
3.I have a schoolbag. I bought it ......... ago.
4.I have had this schoolbag for ........ .
5.I have been studying English for ........ .
6.I have been studying English since
7.Has Tom been studying for ......... time ?
8.How ......... has Anna been sleeping ?