N2
1)yet 2)since 3)ever 4)just 5)just 6)already 7)ever 8)for 9)ever 10)never .
N3
1)i have done my homework ;
2)gretta has walked with her dog
3)galina has travelled a lot
4)the alpinists have travelled to the volcano
5)karr has skied down a mountain
6)i have ridden a cammel
7)carly and sam have swimmed with the dolphins