a1) Fred took his dog for a walk last week2) Mary got up at 7 o'clock yesterday.
b1) Did Fred take his dog for a walk last week2) Did Mary get up at 7 o'clock yesterday?
c1) Fred did not take his dog for a walk last week2) Mary did not get up at 7 o'clock yesterday.
a
1) Fred took his dog for a walk last week
2) Mary got up at 7 o'clock yesterday.
b
1) Did Fred take his dog for a walk last week
2) Did Mary get up at 7 o'clock yesterday?
c
1) Fred did not take his dog for a walk last week
2) Mary did not get up at 7 o'clock yesterday.