Scientific language: verbs

The verbs in the Discussion are more complex than in any other section of the report. The tense may shift from past to present to other verb tenses like the past perfect (had not complied). The verb groups also help to develop the argument in the Discussion by using modal verbs which express different degrees of certainty e.g. 'can', 'may', 'is possible' or verbs like 'appear', 'suggest'. Using verbs like these helps you to be more tentative about the claims you are making.

Here is an extract from a Discussion for the cholesterol experiment. Click on the highlighted text to see the explanation of the verb groups.

In this study, the sample size was small (n=3-4 for each group) and was heterogeneous with respect to age, weight, starting cholesterol concentration and other lifestyle factors. In addition, each subject only consumed either the high- or low-cholesterol diet and a cross-over study would have improved the validity of the data. The greatest problem with this study, however, was compliance. Some individuals indicated that they had not complied with the dietary advice and were omitted from the final analysis but it was impossible to determine how accurate the exact dietary intake of each subject was or even whether they had consumed high- or low-cholesterol foods. Certainly the precise consumption of cholesterol was not monitored and could have varied from week to week.
In a future study, it is recommended that more subjects of both sexes be chosen; that meals of known cholesterol content are prepared for the subjects and that their compliance with the dietary regime be monitored effectively; and that each subject acts as his/her own control by consuming both diets in a randomised, cross-over sequence.

Present tense is used to make generalisations and recommendations.

Past tense is used to describe what happened in this particular experiment.

Past perfect tense is used to describe events that were reported by participants or took place before a particular time in the past.

A modal verb group or a verbs like 'appear' or 'suggest' is used to express tentativeness.

Here is an extract from the Discussion of a report on the experiment for measuring the rate of muscle glycogen consumption during exercise.

Choose the correct form of the verb from the pull-down menus. Some of the verbs are in the active voice e.g. 'shows' and some are in the passive voice, e.g. 'is shown'. Make sure the subject and verb agree and that you have chosen active or passive voice correctly. When you have finished click the Submit button to compare the correct version with your own.


This study that the rate of muscle glycogen consumption during sustained prolonged exercise slower in fitter subjects. Unfit subjects muscle glycogen at twice the rate of the fittest individuals (see Fig. 1) (shown Fig 1). Not only fitter subjects to consume glycogen at a slower rate but they also with more glycogen per gram muscle tissue (Fig. 2). The fittest subject in this study twice the glycogen content of the most unfit. From these measurements the fittest subject to take 4 times as long to deplete all his/her muscle glycogen during sustained exercise if depletion rates constant.

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