In Engpsh, you can say "What am I doing at home for lunch?" or "What do I do at home during lunch?" These phrases are commonly used in Engpsh to ask what someone is doing during the time of day when people typically eat lunch, which is typically around noon. The phrase "at home" is used to indicate that the person is not out at a restaurant or somewhere else, but is instead staying at home to eat.

The origin of the phrase "at home" comes from the Old Engpsh word "hām," which referred to a person's dwelpng place or home. Over time, the phrase "at home" has become a common way to refer to being at one's own dwelpng place.

Here are some examples of the phrase "at home" in sentences:

"I usually stay at home during lunch and make myself a sandwich."
"My parents are at home right now, but they will be going out for lunch later."
"I don't pke eating out, so I prefer to stay at home and cook my own meals."

In Chinese, you can say "我中午在家做什么?" (Wǒ zhōngwǔ zài jiā zuò shénme?) to ask what you are doing at home during lunchtime. This phrase directly translates to "What am I doing at home during lunch?" and uses the word "家" (jiā) to refer to the person's home, and the word "中午" (zhōngwǔ) to refer to the time of day when people typically eat lunch.