It is the same thing , They have just finished their dinner.
They had their dinner.
The past tense for "make" is "made" I made dinner last night. you made dinner last week. she/he/they made dinner last weekend.
Let's look at the verb 'sing'. Past tense - sang Past participle - sung Present tense - sing/sings Present participle - singing Future tense - will sing
The past perfect tense of do is had done.
just is a past tense
Pete and Maria had gone to his house after dinner.
"I had gone for dinner" can be used to say: (past tense) that you went out to get dinner and bring it back - you could instead say: I had gone to get dinner. Alternatively, it could mean (past tense) that you went out to eat dinner - you might want to say: I had gone out to eat dinner. Or, it could mean (past tense) that you were not there for dinner - in this case, a different phrasing could be: I had gone and would not be there for dinner, or, I had gone at dinner time. Please add a comment if you found this helpful, or would like to know more. :)
The past tense of "just now" is "a moment ago" or "just then".
"After" can be used with both present and past tenses. For example, "After I arrived home, I cooked dinner."
Turned is the past tense of turn.
The past tense of the word 'answers' is 'answered'. Example: "I just answered your question."
You should use the past tense: Jeff invited Pete and Maria to his house for dinner.