Auxiliary Verbs

Along with the five verb forms in English an auxiliary verb (sometimes called a helping verb) is used with the main verb to indicate tense, aspect and voice. We can categorise auxiliary verbs in two ways: the primary verbs: be, have and do, and the modal auxiliary verbs.

Be, have and do can be added to other verbs to indicate tense, aspect or voice. Examples:

be      present continuous aspect      the numbers are increasing
be      past passive voice      they were developed
have       present perfect aspect      it has improved
do      past negation      they did not reduce

Auxiliary verbs can be used in combination with each other to express different tenses and aspects. For example:

  • The surface inflow of light Atlantic water is transformed into denser, deeper outflow of Mediterranean water due to evaporation. (present simple passive)
  • Plastic concentrations per surface area were calculated by dividing the total number and dry weight of plastics collected. (past simple passive)
  • Several studies have reported an abundance of plastic in the Mediterranean. (present perfect simple)
  • In the Mediterranean Sea, plastic debris has been found in the stomachs of small fish. (present perfect passive)

We can use the auxiliary verb to avoid repetition.

  • The results showed Facebook social networks reflected real life, but Twitter did not.
  • The US government had not denied involvement, but the German government had.

The auxiliary verb be can also be used with adjective phrases and noun phrases. For example:

  • The partly excavated skeleton was suspected to be a large ape.
  • The incisor teeth appear to be long, like in cattle, but without accentuated edges.
  • The tongue is rather small and pointed, resembling a chimpanzee's.
  • When the sea is calm, plastic is present in nearly all fishing catches in these areas.

The verb be is often used as an existential clause: It is + noun / adjective or There are + noun / adjective to indicate the existence or presence of something.

  • There was no clear association with the main areas of deep-water formation.
  • There are no estimates of plastic pollution for the Mediterranean Sea.
  • It is remarkable that the highest pollution count in the Mediterranean was reported in the earliest assessment.

Modal auxiliary verbs can be used to indicate various meanings of possibility, ability, obligation or certainty (among other things). For example:

  • The lesions in the stomach are not easily explainable but might be related to stress-born problems. (modal of possibility)
  • The service is intended for people who cannot afford to employ an accountant. (modal of ability)
  • Key texts for taught courses must be returned to the Issue Desk. (modal of obligation)
  • Wave- and wind-driven turbulence must also affect the variability in the measurements. (modal of certainty)
  • Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. (modal of possibility)
Test Yourself 1

Complete the sentences with the appropriate form of the auxiliary verb be, have or do. Remember to use the correct tense.

  1. The distribution of the variance can often expose important information that cannot seen in averages.
  2. Some distinctive morphologies were observed that currently  not meet this threshold
  3. Our results suggest that the population growth in online social networks neither significantly determined by population size nor by spatial factors.
  4. In past years online social networks become increasingly important for studying the behavior of individuals.
  5. However, this empirical law, originally observed in economic systems, been challenged by many socio-economic studies.
  6. The right side of the specimen remained buried in the sediment, while the left side exposed to the light of the sun
  7. Initially, our datasets not resolve individual social factors.
  8. Most snail shells show little or no evidence of their original colour under regular light; Conus humerosus is one of the few known species that typically . 
  
Test Yourself 2

Existential Clauses

Choose the correct form of be in the following paragraph containing existential clauses.

Technology Readiness Levels (TRLs)    a series of phases that a research material goes through for a scientist to measure how prepared it is to    offered to the general mass ...

... Each level has specific requirements to be filled before the research material can    advanced to the next stage. Note that the different stages   not discrete levels and cannot be perfectly distinguished like quantum levels ...

... They   rather a continuous flow but with distinctive significance just like a spectrum. The best way to understanding the levels   to follow the steps using an example.