1. We haven't celebrated Christmas for 2 years
2. The last time Linda checked her teeth was in last year.
3. Michelle has collected stamps since 2015
4.
Before Linda sat on the sofa and watched TV, she had made a sandwich.
After Linda had made a sandwich, she sat on the sofa and watched TV.
5. This is the first time my nephew James has drunk beer.
6. David hasn't forgotten his books before.