First teaser trailer for Harry Potter and the Deathly Hallows Part II combines footage from both the final installments and is the same as the theatrical trailer for Harry Potter and the Deathly Hallows Part I. Footage included in the trailer from the second film/part includes (in order of appearance)... There may be spoilers for those who have not read the books.
1. Harry approaches Voldemort in the Forbidden Forest resulting in Voldemort firing the killing curse at him. One of the final scenes in the film.
2. Aged dragon appears in what looks to be Gringotts Wizarding Bank.
3. Group of Death Eaters led by Voldemort, preparing for final battle at Hogwarts.
4. Hermione pushing Ron back in what is likely part of the final battle at Hogwarts.
5. Voldemort launches lightning into the sky. It looks as if Voldemort just stole the Elder wand from Dumbledore's tomb and is testing out its power.
6. Voldemort grabbing Harry: Since the two do not meet until the end of the book, it should be assumed that this scene takes place in Part II.
7. Battle in the Forbidden Forest. Though the battle took place behind the walls of Hogwarts, there is a final confrontation between Death Eaters and the rest of the wizarding world just beyond the outskirts of the Forest. This could be that scene.
8. Cursed fire in the Room of Requirement (right after the "Part 2" font) chases Ron, Hermione and Harry while they attempt to find a Horcrux.
9. All footage after this belongs to the second installment. The final duel shown between Voldemort and Harry is different than what occurs in the book, as their final match takes place inside Hogwarts amongst an army of spectators.