The noun phrases which these prepositions introduce ... In the following examples, however, the prepositional phrase might be preferred as it is more succinct: 'Why are you so late?' ...

[noun, noun, noun] You now know what you need to do to make your sentences parallel: ensure that the co-ordinating units share a common grammatical structure. For number 5, you can choose whether you ...

Some nouns, particularly abstract nouns, have to be followed by a prepositional phrase in order to demonstrate ... which must be used after a particular noun. Occasionally alternatives are possible.