Since it is afternoon he has already eaten his lunch. (past tense). She will have eaten her lunch around noon time. (future tense).
Yes. They can be eaten together at any meal.
12:oo
10Am
Lunch or dinner.
Lunch
That sounds weird. Try lunch is eaten at one o clock.
The past of eat is ate. Future tenses for eat are: will eat -- I will eat my lunch soon am/is/are going to eat -- We are going to eat later. am/is/are eating -- I am eating my lunch after the movie.
Breakfast and Dinner
Lunch and dinner.
lunch and dinner
of Lunch