71.   The letters of the alphabet are representations of sounds.

72.   We received a letter of apology from the company.

73.   The university has sent me a letter of acceptance.

74.   Her teacher gave her a letter of reference.

75.   She traced the letters of her name.

76.   Letters of sympathy were sent to the families of the victims.

77.   I sent her a letter of congratulations.

78.   A stilted letter of apology that was written and accepted with equal measures of insincerity.

79.   The contest editor has jumbled the letters of some common words.

80.   Could I suggest you ask Ribble to send a letter of explanation and apology to the people concerned.