In our every day talks we use words like before, after, early, late, soon, fast, slow, yesterday, today, tomorrow, morning, noon, midnight, past, present, future, last, occasion, frequent, often, usual, always, never, ever, duration, period, era, age, old, young, moment, simultaneous, and many many other words that all contain a common concept so called time.
The first defintion of time in Oxford dictionary is “the indefinite continued progress of existence and events in the past, present, and future regarded as a whole.”
This definition of time contains the key word event that is the clue to realise the concept of time. An event is a snapshot, like a frame in a motion picture film, of changes in our surrendings. And, time is an abstract noun that defines perception of sequence of these events in our mind.