is become 和 is becoming 这两个短语有何区别?

问题描述:

is become 和 is becoming 这两个短语有何区别?

后者更强调一个不曾间断,时刻在变的过程,并且这种变化当下也正在进行中.
前者更强调一种结果性,更轻重于完成时态.