It's as white as snow.

它像雪一样白。

His hair was as white as snow.

他头发雪白。

Her skin was as white as snow.

她的皮肤雪白。

Her skin is as white as snow.

她的皮肤像雪一样白皙。

"As white as snow" is a simile.

“洁白如雪”是明喻。