HSK 7–9 grammar · adverb
极为
极为 — extremely (formal)
Pattern
+
( ) can be left out · other words may come before, between and after
How it works
极为 is a written-style degree adverb meaning "extremely". It goes before a two-syllable adjective or a mental verb, never after it — contrast 极了, which follows the adjective.
Examples
这项技术极为先进。
Zhè xiàng jìshù jíwéi xiānjìn.
This technology is extremely advanced.
他对结果极为满意。
Tā duì jiéguǒ jíwéi mǎnyì.
He is extremely satisfied with the result.
Related

See it in a story
In the app, 极为 is underlined wherever it appears in the stories you read, and practised with sentences from them. Free.