A + 如 + B
如 (rú) used as a verb means "like," "as," or "as if." It draws a comparison or likeness between two things. This usage is literary and appears frequently in idioms and formal writing.
他跑起来快如闪电,谁也追不上。
tā pǎo qǐlái kuài rú shǎndiàn, shéi yě zhuī bú shàng.
He runs as fast as lightning; no one can catch up with him.
时间如流水,一去不复返。
shíjiān rú liúshuǐ, yī qù bù fù fǎn.
Time flows like water, gone and never to return.
她的笑容如春风一般温暖。
tā de xiàoróng rú chūnfēng yībān wēnnuǎn.
Her smile is as warm as a spring breeze.