Put the verb in bracket in the present perfect tense:

VPut the verb in bracket in the present perfect tense:
1.I.....her since last week. (not see)
2. They....this problem for a few days. (discuss)
3. Mr. Nam...in that factory since (not work)
4. I ..my pen since yesterday. (lose)
5. We.. .best friends for a long time (be)
6. He. ......English for five years. (study)