1. die / dead/ dying/ death
(1)die 是终止性动词，不用于被动语态。
He has died.他死了。 He died five weeks ago.他五周前死的。
(2)dead是形容词，表状态，可以跟表示延续的时间状语连用。
His grandfather has been dead for five years.他的祖父去世已经有五年了。
(3)death是名词。
He was sentenced to death.他被判处死刑。
(4)dying意为要死了，是现在分词。试比较：
a dead dog 一条死（了的）狗 a dying dog 一条濒临死亡的狗
初中常见的die短语：die from/ of 因而死