I am confused about past tense vs present perfect.
Both are for completed actions so when to use past tense and when to use present perfect ?
Eg. (a) Anne ate her breakfast (b) Anne has eaten her breakfast.
Hi pixiedust and tianzhu,
I think I will try to address your confusion about the past perfect
and past tense here.
Both actions happened in the past. BUT
- Past tense focuses on actions that have happened in the past in a
specific time frame.
Eg: I drove to the airport last week.
- Past perfect tense focuses on
a) actions that happened in the past
BUT CONTINUED until another action terminated it
b) actions that happened in the past BUT CONTINUED until a certain time in the past.
Eg for a): After I had eaten my breakfast, I went to school.
(You ate your breakfast and it happened in the past and
your eating continued until you went to school,
your going to school terminated your act of
your eating breakfast)
Eg. for b) I had driven my father's car
for the last ten years until last week.
(You drove your father's car until a certain time in the past- last week-
when you stopped).
So in short, an easier way to remember is to think of the
past tense as an action that happened at a specific time in the past
and the past perfect tense is one that was on-going until
another action cut it short or until a certain time in the past.
This is why the past perfect tense is usually used when
there are 2 actions (in the past) in the sentence and
one action was completed before the other action took place.
However for sentences that have result-reason/cause and effect relationships, this is not the case.
Eg: I nearly drowned because I swam too far out to sea.
You do not need to put a past perfect tense for 'swam'.
The cause and effect relationship is one where the cause is
obviously the action that happened first.
And the emphasis is on the cause and effect and
not on the fact that one action had to be completed before another one started.
If you do use the past perfect tense for such a situation,
you are not grammatically wrong. But it is just a little awkward
as there is not need to.
Similarly for relative clauses, they often implicitly display
cause and effect relationships:
Eg: The boy who triggered the fire alarm was scolded (an earlier example tianzhu gave)
The cause of his scolding is him triggering the fire alarm
so it is a cause and effect relationship. Hence there is
no need to use the past perfect tense.