This sentence is an afterthought: green onion mixed with tofu - pure and white.

The color of shallots is half white and half green, while tofu is white, so it is said to be one green and two white. The homophonic pronunciation of green is clear, which forms the idiom "one clear and two white".

The homophonic idiom is one of the most commonly used techniques.

The meaning of this idiom: It is often used to describe someone who is very innocent or has a clear mind.

Similar to this kind of postscript:

The weasel pays New Year greetings to the chicken - no good intentions

Eight Immortals crossing the sea - each showing his magical powers

Ni The Bodhisattva crosses the river - he cannot save himself

Fifteen buckets to fetch water - up and down

Sun Wukong's face - changes at will

Zhu Bajie Look in the mirror - you are not a human being inside or outside

Extended information:

The idioms can be divided into two types:

One is logical reasoning, and the explanation part is The result of reasoning from the previous metaphor. For example:

The narcissus does not bloom - pretend to be garlic

A dumb man eats Coptis chinensis - he cannot express his suffering

All rivers return to the sea - the general trend

The scorpion and the tiger lift the door curtain---show a small hand

There is also a homophonic idiom, which adds homophonic elements to the previous type. For example:

Pouring rice soup into the nostrils - it's enough

Fried dried shrimps - red people (benevolence)

Beating chicken feathers - building courage (pretending to be dusted) Zi

Winter melon rind is used as a steamer - no competition for (steaming) steam

Bean sprouts and fried shrimps (shrimp) - two worthless (straight)

Nephew Lighting lanterns - Still as usual (uncle)

Confucius moved house - a net loss (book)

Baidu Encyclopedia - A postscript