I.
Simple past: she lived - I looked - you bought - he saw - they took
Present Perfect: she has lived - I have looked - you have bought -  he has seen -  they have taken
II.
How often so far' is a signal word for ... Present Perfect Simple
2.     '... ago' is a signal word for ... Simple Past
3.     'Until now' is an signal word for ... Present Perfect Simple
4.     'Yesterday', 'last week' und 'in 2006' are signal words for ... Simple Past
5.     'Just', 'already', 'yet' are signal words for ... Present Perfect Simple
II.
1.     William has already tidied up his room.
2.     Caroline missed the schoolbus yesterday.
3.     I have just finished my homework.
4.     I cannot go out tonight. My grandparents have come to see us.
5.     In 2004, the Olympic Summer Games took place in Athens.
IV.
1.     We did not watch TV last night.
2.     Joanna has not read the book yet.
 

1.
she/live : 
Simple past : she lived
present perfect : she has lived
I/look : 
Simple past : I looked
present perfect : I have looked
you/buy
Simple past : you bought
present perfect : you have bought
he/see
Simple past : he saw
present perfect : he has seen
they/take 
Simple past : they took
present perfect : they have taken
II.Use 
1. 'How often so far' is a signal word for ... Present Perfect Simple
2 '... ago' is a signal word for ... Simple Past
3.'Until now' is an signal word for ... Present Perfect Simple
4.'Yesterday', 'last week' und 'in 2006' are signal words for ... Simple Past
5.'Just', 'already', 'yet' are signal words for ... Present Perfect Simple
III.
1.has already tidied 
2. missed 
3.have just finished 
4.have come
5.took
IV.
1.did not watch
2.has not read