常任的英文：
permanent

参考例句：

The system of Party congresses with regular annual conferences should be tried out in more cities and counties.
扩大在市、县进行党的代表大会常任制的试点。

permanent是什么意思：
adj. 永久的，永恒的，长久的，长期的

It is unchangeable and permanent.
这是持久不变的。

a permanent diplomatic mission
常驻外交使团

There is nothing permanent except change.
除了变动外别无永久之事。

There is nothing permanent except change
变幻才是永恒

Are you planning to settle permanently in this country?
你准备在这个国家定居吗?