他們那麼年輕。

They were so young.

Source: Tatoeba

Sentence Composition

1 他們 tāmen they; them
2 那麼 nàme
  1. like that; in that way; to that extent
  2. (before a number) ... or so; about ...
  3. then; in that case
3 年輕 niánqīng young