76.The senior students can behave well even in the a of their head teachers.
absence
句意为：高中生即使是在没有老师的情况下也能够表现的很好。in the absence of，无......时。
此题考查对语境的理解．准确理解语境，根据首字母确定单词。
句意理解不到位，短语掌握不准确。