"Where is she?" is how you would ask "她在哪里" in English. This question is formed using the pronoun "she" to refer to a person, and the verb "is" to indicate a state of being. The adverb "where" is used to ask about the location of that person.

Here are some example sentences using this construction:

"Where is she?"

"I don't know where she is."

"Can you tell me where she is?"

"She is at home."

In these sentences, the person being referred to as "she" is the subject of the sentence, and the verb "is" is used to indicate her location. The adverb "where" is used to ask about that location.

This construction is common in English and is used to ask about the location of a person, object, or other entity. It is derived from the basic rules of English grammar, which dictate the use of pronouns, verbs, and adverbs to form sentences and ask questions.