The adverb 相当 "quite"
相当 is an adverb of degree (程度副词). It used to emphasize a feature of an object or the degree of an emotion.
The adverb 相当 
is placed before a predicate expressed by an adjective.
is placed before a predicate expressed by an adjective.
Scheme
subject
相当
predicate
Examples
今天天气相当暖和
The weather is quite warm today
jīntiān tiānqì xiāngdāng nuǎnhuo
这个冰箱相当不错
This fridge is quite good
zhè ge bīngxiāng xiāngdāng búcuò
这篇文章相当难懂
This article is quite difficult to understand
zhè piān wénzhāng xiāngdāng nándǒng
相当 is part of the verb 相当于 .
.Examples
你的智力只相当于五岁的孩子
You have the intelligence of a five-year-old child!
nǐ de zhìlì zhǐ xiāngdāngyú wǔ suì de háizi
Learn more