Answer:
1.I have written articles on different topics.(present perfect tense)
2.by 6 o'clock, i will have finished my work.(future perfect tense)
3. i will have prepared breakfast by the time the children wake up.(future perfect tense)
4. I have travelled quite a bit in the East" (present perfect tense)
5.The police are still they have investigatedthe murder. (past perfect tense)
