In this task, you will use your knowledge about language (and common sense) to determine what element the marked number refers to. The numbers are marked with two underlines around them, like: _ number _. Your answer should be chosen from the given text, and should not contain other words.
One example: Jess Mastriani: No, I don't want another crooler, thank you very much.
FBI Agent Nicole Scott: But it's good for you. It's got... honeyglaze. Please die for this crooler, Jess.
Jess Mastriani: I've had _ two _ already. Who eats three croolers in a night?
FBI Agent Nicole Scott: Take a look. [Nicole takes a huge bite] Mmmmm, Mmmmm, Mmmmm!
Solution is here: crooler
Explanation: In this example, the number two refers to something that the word: crooler.

Now, solve this: The Doctor: I just want you to know , there are worlds out there , safe in the sky because of her . That there are people living in the light , and singing songs of Donna Noble , a _ thousand _ , million light years away . They will never forget her , while she can never remember . And for one moment ... one shining moment ... she was the most important woman in the whole wide universe .
Sylvia Noble: She still is . She 's my daughter .
The Doctor: Then maybe you should tell her that once in a while .
Solution:
years