有關 have just 同埋 had just 的問題

Have just finished ( past particple) <-- PRESENT perfect tense
- I have= 已經just finished my homework. ( a complete action)
Mom, I have已經 just finished my homework. May I watch TV now?

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Had just finished ( past particple) <---------PAST perfect tense
Example
When I arrived home, my father had just left( this had happened in the past)
my father had just left <------------------ first action
when I arrived home<------------------second action

They are two different tenses.<--------------
我剛剛在上個暑假讀完博士學位 的 英文是咩？
You don't have to say " 剛剛" here.

Last summer <------- refers to the PAST
" Simple past tense" would be proper.
Last summer I earned/obtained my doctorate.
or
I earned/obtained my doctorate last summer.
博士學位= DOCTORATE <--------------------
last summer <--------------Correct!
on last summer<----------------WRONG!

2009-02-02 17:14:18 補充：
Have just finished ( past participle) <-- PRESENT perfect tense***

have (just) + verb to be = present perfect tense.
e.g. I have just finished my homework on today.

had ( just) + verb to be = past perfect tense
e.g. I had just finished my homework after dinner on yesterday.



I had just finished my Master Degree on last summer.