Translation:It's six o'clock.
"o'clock" should always be listed as one word, in English the apostrophe joins/abbreviates words into one, just like; it's, isn't, don't and can't. You would never see them written as two separate things, as well as "o" is not a word on it's own, neither is " 'clock" it is the shortening of the phrase "of the clock".
The R doesn't sound like a D at all, not even a little bit. It sounds like the "Voiced alveolar flap" (IPA: /ɾ/), which is the same sound used for the letter R in almost all languages other than English. Alternatively, the Japanese may sometimes use the allophone "Voiced alveolar lateral flap" (IPA: /ɺ/).
You can hear the pronunciation of these and many other phonemes on this nice website: https://www.ipachart.com/