81.I wrote him a letter to show my ____ of his thoughtfulness.

A.achievement B.agreement C.attention D.appreciation

82.I'm sorry I stepped outside for a smoke.I was very tired.

There is no _____ for this while you are on duty.

A.reason B.excuse C.cause D.explanation

81.答案是D,此题考查词汇，appreciation,欣赏，感激。

82.答案是B,此题考查词汇，excuse,借口，托辞。