Questions about example sentences with, and the definition and usage of "Mistook"

A: Mistook is the past tense of mistake. It means the person made a mistake and thought the shampoo was the conditioner.

A: I thought he was Justin when I first saw him.

A: You thought he was someone you knew. He was not who you thought he was.

A: sorry, (I have mistaken - I thought you were someone else) these are enough to deliver the meaning

A: I mistook the compliment as an insult.
I had mistaken the yarn for a thick string.

A:
I confused an apple WITH an orange. (I forgot which one is an apple, and which one is an orange)
or
I mistook an apple FOR an orange. (It was an apple, but I called it “an orange “)

A: I have never heard or said mistook before.

It is the past tense of mistake.

I mistook his breathless state as an indication of passion.

A: “mistook” is for when you confuse (usually two) things for one another, usually because something ressembles something else.
e.g. I mistook the girl with glasses for my sister.

“misunderstood” is for when you are confused about an idea or concept.
e.g. I misunderstood the rules of the game.

A: 'mistook' is the past tense of 'mistake'. So the rules of grammar insist that these two sentences mean the same.

Ahora bien, nobody says sentence 1 and everybody says sentence 2.

A: "He mistook me as Chinese" would sound more natural. Here are some other examples with "mistake for":
1. We mistook him for a kind and innocent person.
2. She's always mistaken for her sister.
3. I was mistaken as the little girl's mother.
4. They mistook me as someone who gives up too easily.
5. He mistook my brother for his friend because they look similar.

A: "I think you have/you`ve mistaken me for someone else" or "I think you have me confused with someone else"

A: "I mistook today as Monday"
"i thought today was Monday"

A: "Mistook" and "wrong" kind of make a double negative. Also I think the prepositions in "for socks" and "the stock" might not be the best. Plus "to our company" probably isn't needed. Additionally, I think the customer will be curious whether you plan to return their money or send them the correct socks.

"​​I'm really sorry that I sent you the wrong color of socks.
I will confirm our stock and tell you how to return them"

(Too bad about the scolding)

A: @ZooeyPan: "at first" means "the first time"

older = more old

The first time I saw/met you, I thought you were more old, but you are actually not more old. You are more young than I thought you were at first.

I mistook it for a bird at first sight.

mistook = MIStakenly thought. incorrectly thought.

I mistakenly thought it was a bird the first time i saw it. its not a bird.

A: よく分かりませんが、you chose the wrong person to pick a fight withかな？

A: We never use the second one. In fact both are rather formal.