In scientific and technical writing the choice of verb tenses is quite limited.* when presenting results, if the findings are general facts
In cases when the eigenvalue of interest is well separated from the others, K2 tends to increase the
natural frequencies of the forward and backward waves but decrease the natural frequency of the
reflected wave, just opposite to the effect of M2.There are differences in the way the passive and the active forms are used:
* the present simple passive is used when describing a process or procedure (see
Section 4.4 on the Passive Voice)
* the present simple active is preferred in physical descriptions, such as describing a
piece of apparatus or equipment
The plotter represents another important output device.The perturbation method we develop here applies to any crack geometry as long as the crack-face
weight function solutions are known for the corresponding reference crack.(See Section 5.4 on Passive Voice)
In Fig.4 the uniaxial curve was calculated using Eq. /51/, the deviatoric stress-strain curve was
calculated using Eq./20/, and the hydrostatic stress-strain curve was calculated using Eq./52/.* NOTE: Do not use the future tense in the subordinate clause in time or conditional
sentences (with When ... or If ..., etc.)
The real value of the spreadsheet will be seen when the next survey is conducted.* when making general statements, e.g. in conclusions
This observation indicates an obvious inconsistency that is avoided by the introduction of generalised
principles.You use this when referring to specific tasks carried out, such as taking measurements,
conducting experiments, describing methods actually used, or presenting your results and
conclusions from the particular piece of work.Experimental results were obtained by the use of surface wave transducers, which were placed on
two perpendicularly intersecting faces of a polished aluminium block.* The past tense is also used in the introduction to give historical background or
development in the field of interest:
Technologists and craftspeople of early civilisations built huge objects.This
paragraph
* summarises the purpose of the paper (in the past tense),
* states the current state of development in the area of interest (present perfect),
* indicates the aim of the paper (future tense), and
* reports the results performed by the authors (past tense).Therefore,
use it in the following situations:
* when writing about your topic or background
Lasers are devices which amplify light and produce beams of light which are very intense, directional,
and pure in colour.The author believes that one particular application, where the results can be useful, is the modelling
of contact problems involving anisotropic materials.* The past tense is commonly used in acknowledgements:
The work, which led to this paper, was sponsored by the Natural Sciences and Engineering Research
Council of Canada.* when explaining your purpose
Here we investigate the properties of the above mentioned metals.The plotter makes hard copy of the product
represented by digital information in the computer.62Grammar
* The past simple passive is mainly used when we report a particular procedure related
to only one particular occasion in the past.Algebra and trigonometry were
well understood and applied during those early years.Construction of the pyramids of Egypt and of
Central and South America required experience and the labour of many people.* It is commonly used in the introduction, particularly when you want to recapitulate
the state of the art and show what work has been done and is still in progress.The most
commonly used tenses are
?It is used to state facts that are generally valid from the point of view of the writer.Most CAD systems use a pen plotter.This financial support is greatly appreciated.Little is known about HPS systems , which are the subject of the following chapter.the simple present
?the simple past
?the present perfect.How is the present tense used?How is the past tense used?I started my research at the beginning of this term.How is the present perfect used?