Subject + 为 + Noun/Adjective
为 (wéi) means "to be," "to act as," or "to serve as" and is used in formal or literary Chinese. It functions similarly to 是 but carries a more formal tone. It also appears in many set expressions and compound words like 认为 (to think/consider) and 以为 (to assume).
此举被认为是一大进步。
Cǐ jǔ bèi rènwéi shì yī dà jìnbù.
This move is considered a major step forward.
大家一致认为这个方案最好。
Dàjiā yīzhì rènwéi zhège fāng'àn zuì hǎo.
Everyone unanimously agreed that this plan is the best.
他以为我不会来。
Tā yǐwéi wǒ bù huì lái.
He thought I wouldn't come.