Almost one in five adults don't know the difference between a verb and a noun, a survey has found.

       Research has been conducted into the longevity of learning as children prepare to return to school, with results revealing that a large proportion of UK adults have forgotten key elements of grammar.

       It was found that 17 per cent of adults do not know the difference between a noun, a verb, and an adjective.

       Noun as objects, adjectives as descriptive, and verbs as “the doing word” are all taught to primary school children ahead of more complicated grammatical ideas.

       UK adults, according to research by children's stationery brand Stabilo, fared even worse when trying to recall these other building blocks of language.

       Almost one in three polled adults in the survey stated that they could not define an adverb.

       It was also found that a fifth were unable to quote anything at all from William Shakespeare’s works.

       Vanya Hunter, with Stabilo UK, said: “This research is fascinating, highlighting the things which many have forgotten.”

       Other forgotten lessons included basic algebra and trigonometry, the least remembered of all subjects in the survey, with around half of adults unable to remember these elements of maths.

       Pythagoras’ theorem, long division, and how to calculate Pi had also been forgotten by around a third of adults, according to the survey.

       Naming ten or more elements on the Periodic Table was too much for 32 per cent of those surveyed, and the various types of triangle had been forgotten by 25 per cent.

       Maths and science again proved difficult for the 23 per cent who could not recall the difference between amps and volts, and the same proportion who could not multiply decimals.

       Geography was also forgotten, with 22 per cent no longer able to recall what an oxbow lake was, or name the different kinds of clouds, and less than 20 per cent could remember the basic principles of rock formation or photosynthesis.