Expressing “extremely” with 极端 and 极度
The adverb 极度
The adverb 极度 
is stated before the predicate and expresses the highest degree of something.
is stated before the predicate and expresses the highest degree of something.Examples
人人都处于极度兴奋之中
Everyone is in a state of extreme excitement
rén ren dōu chǔyú jídù xīngfèn zhī zhōng
她极度疼爱自己的儿女
She loves her children very much
tā jídù téng ài zìjǐ de érnǚ
表面上自信，内心极度紧张
He is confident on the surface, but extremely nervous inside
biǎomiàn shàng zìxìn, nèixīn jídù jǐnzhāng
The word 极端
We can use 极端 either as an adverb or an adjective.
either as an adverb or an adjective.As an adverb
As an adverb, it has the meaning of “extremely”.
Pay attention
When 极端 is used as an adverb, it is usually has a negative connotation.
Examples
我认为这是极端不明智的
I think this is extremely unwise
wǒ rènwéi zhè shì jíduān bù míngzhì de
他极端迷信，认为绿色带来厄运
He is extremely superstitious and believes that green brings bad luck
tā jíduān míxìn, rènwéi lǜsè dàilái èyùn
The adjective
As an adjective, 极端 has the meaning of “extreme", "radical”
Examples
它们不受极端气温的影响
They are not affected by extreme temperatures
tāmen bú shòu jíduān qìwēn de yǐngxiǎng
需要采取极端的措施来整顿这个行业
Extreme (radical) measures need to be taken to reorganize the industry
xūyào cǎiqǔ jíduān de cuòshī lái zhěngdùn zhè ge hángyè