21.00 twenty-one (hundred) hours

[sitifan]

The time of day
8.00 a.m. eight a.m. /eight o’clock in the morning
10.00 p.m. ten p.m. /ten o'clock in the evening.
7.30 half past seven/seven thirty
half seven (informal)
7.15 (a) quarter past seven/seven fifteen
7.45 (a) quarter to eight/seven forty five
9.20 twenty (minutes) past nine/nine twenty
9.55 five (minutes) to ten/ten fifty five
10.23 twenty-three minutes past ten/ten twenty-three
10.46 fourteen minutes to eleven/ten forty-six
16.08 sixteen oh eight
21.00 twenty-one (hundred) hours

(A Basic English Grammar, by John Eastwood and Ronald Mackin, page 143)

Does the quotation in red mean that 21.00 can read either "twenty-one hours" or "twenty-one hundred hours"?

[Tarheel]

Twenty-one hundred or twenty-one hundred hours

Google "military time".

[emsr2d2]

21.00 twenty-one (hundred) hours

(A Basic English Grammar, by John Eastwood and Ronald Mackin, page 143)

Does the quotation in red mean that 21.00 can read either "twenty-one hours" or "twenty-one hundred hours"?

It certainly appears to be what they're suggesting but I disagree with them. If it's exactly 9pm, then it's only worded "twenty-one hundred hours", and only when using "military time". From 9.01pm onwards, the hundred would be omitted. 2105 = twenty-one oh five.

[PeterCW]

I agree, BrE usage would be "twenty-one hundred" or more likely to read it aloud as "nine PM".

"Military time" is an American expression which would cause most British people to be puzzled. Twenty-four hour times are universal in transportation schedules in Europe and most of us will happily switch between systems in mid conversation.

[Tdol]

21.00 twenty-one (hundred) hours

Does the quotation in red mean that 21.00 can read either "twenty-one hours" or "twenty-one hundred hours"?

It does, but I would say it should be twenty-one hundred (hours).

[emsr2d2]

"Military time" is an American expression which would cause most British people to be puzzled.

I think quite a lot of BrE speakers would understand it but it's certainly more common to the use the term "the 24-hour clock".

Bob: How would you express 9pm using the twenty-four hour clock?
Jane: Twenty-one hundred [hours].

[SoothingDave]

I don't think anyone is saying "fourteen minutes to eleven" for 10:46. Five till, ten till, quarter till all are natural. Not numbers not divisible by 5.

[Skrej]

I agree with Dave. I obviously can't speak for everyone, but I tend to round to the nearest unit of 5 for that very reason, unless there's a need to be precise. If so, then I'll just use the straight number format, and not mess with the to/past format.

For example, at 10:46, I'll just say "(about) a quarter to 11". If I need to be exact, then "10:46" For something like 10:08, then it's either "10 past ten" or "10:08".

I'm writing this post at a quarter past 5 local time. (But it's really 5:17 by the clock on my wall.)

[Rover_KE]

21.00 twenty-one (hundred) hours

Does the quotation in red mean that 21.00 can be read either "twenty-one hours" or "twenty-one hundred hours"?

I haven't read every word of this thread closely, but I don't think anybody says 'twenty-one hours'.

[Tdol]

I'm writing this post at a quarter past 5 local time. (But it's really 5:17 by the clock on my wall.)

I'm analogue with time and round things off, but, apparently, some younger people are so digital they don't really know how to read an analogue clock.