48 Science Research Writing both, and the agent of the action is not mentioned in the sentence — we don't add 'by the researcher' or 'by me' at the end. Passives used in formal writing are normally of this type, i.e. agentless passives. However, because the agent is not given, the only way that the reader can separate what is normally done (Sentence (a)) from what you did yourself (Sentence (b)) is if you use the correct tense. Check your target journal, but wherever possible it is clearer to use the Present Simple passive for what is normally done and the Past Simple passive to indicate what you did yourself. You can see that if you don't pay careful attention to the tense of these sentences, your own work may become confused with the standard procedures you are describing. Th is is a very common error, even among native speakers, and has serious consequences. If the reader cannot identify your contribution, that is a disaster! Look at this example: Two dye jets are placed in the laser cavity. A gain jet is then excited by an argon ion laser and the pulses are spatially fi ltered in order to obtain a Gaussian beam. Polarisation is confi rmed using a polarising cube. Th e pulses were split into reference pulses and probe pulses and the reference pulses were carefully aligned into the detector to minimise noise levels. In this case, splitting the pulses into two groups for testing was the signifi cant innovation of the writer's research team but the only way the reader knows this is because of the change in tense from Present Simple passive to Past Simple passive (were split). Here is another example: Samples for gas analysis were collected using the method described by Brown (1999), which uses a pneumatic air sampling pump. Another diffi culty arises with the passive when you write about the procedure you used and compare it with the work of other researchers. You can use the Past Simple agentless passive to describe the procedure you used (the samples were collected using a suction tube) but you may also need to use exactly the same Past Simple agentless passive to describe the procedure used by the other researcher whose work you are citing (the samples were collected using a suction tube). Th is means that unless you are very careful, the reader has no way of separating your work from that
Methodology — Grammar and Writing Skills 49 of the other researcher. Th e fact that you are so familiar with what you did means that your own contribution is obvious to you — but it may not be obvious to your reader. One way to make sure that your own contribution is clear and easy to identify is by marking it with words — perhaps by adding phrases like In this study, the samples were collected using a suction tube or In our experiments the samples were collected using a suction tube, and by identifying the procedure used by other researchers with careful references at the appropriate place in the sentence (In Brown (1999) the samples were collected using a suction tube). Th ere are fi ve possible uses that you may need. Note the diff erent tenses. What do you mean? How can you make it clear? 1 X was (collected/ substituted/ adjusted etc.) by me in the procedure or work that I carried out Either move to the active (We collected/adjusted/ substituted etc.) or add words or phrases such as here/in this work/in our model or use a 'dummy' subject such as Th is experiment/Th e procedure 2 X was (collected/ substituted/ adjusted etc.) by the person whose procedure or work I am using as a basis for, or comparing with, my own Give a research reference and/ or add words/phrases such as in their work/in that model 3 X is (collected/substituted/ adjusted etc.) normally, i.e. as part of a standard procedure You may need a research reference even if it is a standard procedure, depending on how well- known it is. Use phrases such as as in 5