Learn to talk about time and ask the time in English (requires Real Player).
On the hour
Past / to the hour
Prepositions
What to say
Work Time
Writing the time
Time Idioms

Time (1)

When it's "on the hour" we say "o'clock". But only when it's on the hour.

12 o'clock Twelve o'clock 12 o'clock Six o'clock
12 o'clock One o'clock 12 o'clock Seven o'clock
12 o'clock Two o'clock 12 o'clock Eight o'clock
12 o'clock Three o'clock 12 o'clock Nine o'clock
12 o'clock Four o'clock 12 o'clock Ten o'clock
12 o'clock Five o'clock 12 o'clock Eleven o'clock
Because it can be difficult to say whether 12 o'clock is during the day or the night, we use two special terms.
12 o'clock 00:00 and 24:00 = Twelve midnight (or midnight) 12 o'clock 12:00 = Twelve noon (or noon)

Time (2)

In five minute increments, when it's past the hour (up to 30 minutes past) we say "past".

When it's before the hour (after 30 minutes past) we say "to".

There are 60 minutes in an hour.

30 minutes is half an hour, we say "half past" or "thirty".

15 minutes is quarter of an hour, we say "quarter past" or "fifteen" or "quarter to" or "forty-five".

Clock past to
12 o'clock Twelve o'clock 12 o'clock Twelve fifteen

or

Quarter past twelve
12 o'clock

Twelve thirty

or

Half past twelve

We never say "half to".

12 o'clock Twelve forty-five

or

Quarter to one
At other "odd" times, when we want to be accurate, we add the word "minute(s)":-
Telling the time It's twenty-eight minutes to twelve. Telling the time It's one minute past three.
If you want to avoid trying to remember when to use "minutes" and when not to just say "nearly" or "just turned".  
Telling the time It's just turned half past eleven. Telling the time It's nearly three o'clock.

 

Prepositions used with time

At a point in time In a length of time
"When shall we meet? 12 o'clock "Let's meet at 12.30." "It's 12.45, when will you be ready? 12 o'clock "I'll see you in an hour, at about 1.45."

Naturally speaking

Digital clocks often show the time this way using the 24-hour-clock, only the police and the military actually speak using the 24 hour clock:-
If it's before noon we tend to say "in the morning". If it's after noon we say "in the afternoon". If it's late we say "at night".
07:00
It's seven o'clock in the morning.
14:00
It's two o'clock in the afternoon.
22:00
It's ten o'clock at night
15 minutes past the hour is quarter past:    
07:15
It's quarter past seven in the morning.
14:15
It's quarter past two in the afternoon.
22:15
It's quarter past ten at night.
30 minutes past the hour is half past:    
07:30
It's half past seven in the morning.
14:30
It's half past two in the afternoon.
22:30
It's half past ten at night.
45 minutes past the hour is quarter to:    
07:45
It's quarter to eight in the morning.
14:45
It's quarter to three in the afternoon.
22:45
It's quarter to eleven at night.

 

How to ask the time in English.
12 o'clock
  • It's exactly eight o'clock.

or
  • It's eight.

12 o'clock
  • It's half past twelve.

or
  • It's twelve thirty.

12 o'clock
  • It's about half past eleven.

or
  • It's around eleven thirty.

Work time

There are some common words and phrases that we use to describe the hours we work.

At work in the UK we talk about starting time and leaving time.

9-to-5 is a phrase used to describe a conventional and possibly tedious job. Negatively used, it connotes a tedious or unremarkable occupation, the idea being that, because the job is so boring, the workplace shuts down outside of required hours. The phrase also indicates that a person is an employee, usually in a large company, rather than self-employed. More neutrally, it connotes a job with stable hours and low career risk, but still a position of subordinate employment.

Overtime is  the time we work in addition to what is normal. Overtime is either paid, or unpaid.

Full time (full-time) is the term we use to describe the whole of someone's available working time, typically 40 hours in a week, but the European Union's working time directive imposes a 48 hour maximum working week that applies to every member state except here in the United Kingdom (which has an opt-out meaning that UK-based employees may work longer than 48 hours if they wish, but they cannot be forced to do so).

Part time (part-time) is the term we use to describe employment with fewer hours per week than a full-time job. 

Time off is the term we use to describe time for rest or recreation away from one's usual work or studies.

Time in lieu refers to taking time off instead of, or in addition to, receiving pay for overtime worked or working on public or bank holidays. 

Check these time idioms too.

Writing the time

morning 00:01 - 11:59
a.m. - stands for Ante Meridiem (the time between midnight and noon) 00:01 hrs - 12:00
noon or midday 12:00
p.m. - stands for Post Meridian (after noon) 12:01 - 24:00 hrs
afternoon 12:01 - 18:00
evening 18:01 - 22:00
night 22:01 - 24:00
midnight 24:00 / 00:00

There are 24 hours in a day, but only the military, police and computer programmers use the 24-hour clock. When writing or speaking generally we tend to use the 12-hour clock. The 24 hours of the day are divided into two periods called a.m. (Latin "ante meridiem" | English: "before mid day") and p.m. (Latin "post meridiem" | English: "after mid day").

The way people write the time varies. I prefer a.m. and p.m.

Choose from the following styles or use what your English teacher tells you to and stick to it:-

a.m. p.m.
am pm
AM PM
A.M. P.M.

Some people use a dot as the separator: 2.30 pm.

Some people use a colon as the separator: 2:30 pm. The colon is usually used with the 24-hour clock: 14:30.

When you are writing the time decide whether to write it using numerals or words, and stick to that.