"He is not happy" 可以用来表示他很不快乐。这是一个常见的表达方式，来自英语的基本语法。
下面是一些英文例句，并附上中文翻译：
"He looked sad and unhappy when I saw him yesterday." 他昨天看起来很悲伤和不快乐。
"She has been unhappy at her job for a long time, and she finally decided to quit." 她在工作中很不快乐很长时间了，最终决定辞职。
"He tried to hide his unhappiness, but I could tell something was wrong." 他试图隐藏他的不快乐，但我能感觉到有些事情不对劲。
下面是一些英文例句，并附上中文翻译：
"He looked sad and unhappy when I saw him yesterday." 他昨天看起来很悲伤和不快乐。
"She has been unhappy at her job for a long time, and she finally decided to quit." 她在工作中很不快乐很长时间了，最终决定辞职。
"He tried to hide his unhappiness, but I could tell something was wrong." 他试图隐藏他的不快乐，但我能感觉到有些事情不对劲。