o clock is unnecessary. if you are talking about time you don't have to say it. people generally don't
"the time is" is not accepted. Kello on means the time is, not just it is. Both should be accepted.
it is and the time is are in this case interchangeable
It's o' clock, not o 'clock. The apostrophe stands in for the missing "f the" in "of the clock".
Is the second it is necessary - I would have thought that "It is evening and exactly eight o'clock" would have been a reasonable translation?
'the time is' is still not accepted. It should be
It is eight on the dot - should be also accepted.
Tendency as slang
O'clock is not considered a compound for about 200 years in english, o'clock is always used as a single word.
I keep getting dinged for missing one or other bit! Please fuse it and offer just "clock" and " o´clock " as choice options.