(simple past--historical fact)
(present perfect--from past until present)
(simple past--completed action, finished time period)
(present perfect--recent past action affecting/related to present)
(present perfect--from past until present)
(past perfect--past even completed before a second past event)
(past perfect--past even completed before a second past event)
(simple past--past actions connected to each other)
(past perfect--reported speech of completed past action)
(present perfect--from past until present)
a. completed
b. had completed
c. have completed
d. was completed
(present perfect--recent completed action)
a. tried to
b. had tried to
c. have tried to
d. try to
(simple past--past actions connected to each other)
a. were you listening
b. had you listened
c. have you listened
d. do you listen
present perfect--from past until present
a. had go
b. has been
c. would go
d. had been
(past perfect--reported speech of completed past actions)
a. ate
b. had eaten
c. have eaten
d. was eating
(past perfect--unconnected past actions)
(simple past--past actions connected to each other)
(present perfect--recent past action affecting/related to past)
(past perfect--unconnected past actions)
(past perfect--past even completed before a second past event)
(present perfect--recent completed action)
(past perfect--reported speech of completed past action)
(present perfect--from past until present)
(simple past--completed action, finished time period)
(past perfect--unrealised past hope)