Exercício: For - During

Estou na duvida em resolver estes exercicios:
Use For ou During:

Millions os people were Killed _______ World WAr
Drinks will be served________the intermission
I haven´t seen David________ages!
People will remenber that day________a long time
The actor had a heart attack________the first act of the play
We´ll study a lot of poems_____the course
I don´t want to meet any of my patients_____my cacation
He stopped smoking_____good
______thei conversation they discovered they had studied in the same school
He stayed in prision_______ six months