Below is a list of letter pairs, each pair of letters represent a word where one letter is the 2nd letter, and the other is the 4th letter, (the order of the letters in each pair of brackets may not always be correct).

Determine what is being represented by the different pairs of letters.

(H,L)(R,V)(R,H)(E,T)(C,O)(O,T)(F,O)(O,E)(N,I)(U,I)(I,O)