do đó

do (“because”) +‎ đó (“that”).

• (Hà Nội) IPA^(key): [zɔ˧˧ ʔɗɔ˧˦]
• (Huế) IPA^(key): [jɔ˧˧ ʔɗɔ˨˩˦]
• (Saigon) IPA^(key): [jɔ˧˧ ʔɗɔ˦˥]

• Audio (Saigon):

  (file)

do đó

1. therefore; thus; hence; as a result; as such

   Synonym: vì thế

Although do and vì are practically synonyms, only do đó and vì thế are idiomatic, not *do thế and *vì đó.