67. According to the author, what is the reason that lexical phrases prove highly motivating?
(A) Lexical phrases may be treated as whole, preassembled units like words.
(B) Lexical phrases can be produced afresh using the rules of syntax.
(C) Lexical phrases offer learners the possibility of developing fluency without rich linguistic resources.
(D) Lexical phrases can be fixed formulaic phrases or combinations of semi-fixed words.