Writing about the past

Writing about the past in English is made difficult by the rather complex tense system. However, the phrases grouped below give an indication of the uses of the main tenses in academic writing. For a comprehensive explanation of the uses of the various tenses you will need to consult a good English grammar book. A good recommendation is Practical English Usage by Michael Swan, Oxford University Press.

Time phrases associated with the use of the simple past tense: specific times or periods of time in the past
In 1933,
Three years later,
From 1933 to 1945,
In the 1930s and 1940s,
During the Nazi period,
Between 1933 and 1945,
restrictions were placed on German academics.


For centuries,
Throughout the 19th century,
At the start of the 19th century,
In the latter half of the 19th century,
At the beginning of the 19th century,
Towards the end of the 19th century,
In the early years of the 19th century,
At the end of the nineteenth century,
In the second half of the 19th century,
authorities placed restrictions on academics.
Time phrases associated with the use of the present perfect tense: past and present connected

To date, little evidence has been found associating X with Y.
Up to now, the research has tended to focus on X rather than on Y.
So far, three factors have been identified as being potentially important: X, Y, and Z.
Since 1965, these four economies have doubled their share of world production and trade.

Until recently, there has been little interest in X.
Recently, these questions have been addressed by researchers in many fields.
In recent years, researchers have investigated a variety of approaches to X but …
More recently, literature has emerged that offers contradictory findings about …

The past decade has seen the rapid development of X in many …
Over the past 30 years there has been a significant increase in …
Over the past century there has been a dramatic increase in …
Over the past few decades, the world has seen the stunning transformation of X, Y and Z.

The present perfect tense is typically used to describe recent research with several contributors

Previous studies of X have not dealt with …
Several recent studies have revealed that
It has been shown that … (Smith, 2002, Jones, 2007).
X has been intensively investigated recently due to its …
A considerable amount of literature has been published on X.
X has been identified as a major contributing factor for the decline of …
Factors thought to be influencing X have been explored in several studies.
The new material has been shown to enhance X (Smith, 2002, Jones, 2007).
The relationship between X and Y has been widely investigated (Smith, 2002, Jones,
There have been several investigations into the causes of X (Smith, 2005; Jones, 2007).

For reference to single investigations or publications in the past, the simple past tense is used
The first detection of X came in 1992 when …
systematic study of X was reported by Smith et al. in 1992.
experimental treatment of X, by Smith et al. (1992), used a …


In 1969 Smith et al. performed the first …
published a paper in which they described …
introduced a system of classification based on …
demonstrated that X induced in vitro resistance to …