就任的英文：
take office
assume a post

参考例句：

He assumed office as president amid national rejoicing.
他在举国欢腾中就任总统。

When Nixon assumed the Presidency, "Bus" wheeler was in his final year as Chairman of the Joint chief
当尼克松就任总统时，“巴士”惠勒最后一年当参谋长联席会议主席。

Accede to a governor ship
就任地方长官的职务

When did the ambassador come in?
大使是什么时候就任的？

induction into the presidency
总统就任仪式

He has been installed in his new office.
他已就任新职。

accede to the chancellorship
就任大臣、 大学名誉校长等.

Induct a clergyman to a benefice
使牧师就任有俸禄的圣职

He was installed as president yesterday.
他昨天正式就任校长。

He will be inaugurated as president in January.
他将在一月就任总裁.

take是什么意思：
v. 拿，取；带；获得；采取；承担；吃；耗费；乘，搭；以为；理解；走；抓住

a catch; a take; a taking
捕获量

take a nap; take a snooze
小睡一下;睡午觉

take service with
在￥帮佣

assume是什么意思：
v. 假定；臆断；采取；承担；呈现；夺取，继承；装腔作势

The responsibility for the accident was assumed by me.
事故责任由我承担。

To state or assume as a proposition in an argument.
假设，预设命题在论证中做为一命题陈述或假设。

take up (=assume) this mission
承担这使命