the start or beginning of …

the onset of …

the end of …

at any time

at any given time

at any one time

the first stage of …

concurrent

simultaneous

a contemporary account of …

Shakespeare’s etc. contemporary

consecutive

in chronological order

the project was completed on time

Duration

between … and …

from … to …

an interval of … seconds, hours etc.

over the course of … five weeks, one year etc.

a 24-hour period

for or during the entire period

during the study

for the duration of the experiment

to change over time

to evolve over time

a brief period of …

a rapid development

a time of rapid change

a swift decision to …

a continuous process of …

chronic poverty, illness etc.

a temporary measure

… is only a short-term solution to …

… has been plagued by short-termism

a long-term problem

long-term change proved to be more difficult …

a or one persistent problem in … is …

eventually led to …

in the long run

a permanent solution

The problem was eventually solved by …

a period of stability or great change

the … period is usually defined as …

the Elizabethan etc. era is or was characterized US and GB or characterised GB by …

… spans several decades or centuries

an age of …

a new epoch

the end of an epoch

Next: Frequency

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