"The physician started to perform the operation, but the patient was not yet completely under anesthesia."
The question asked to identify the incorrect word or phrase in this sentence, however, there is nothing that really strikes me as "wrong". I'm not exactly sure what grammar rule I'm overlooking here.
I don't see any errors, either — well, unless these words —> "yet completely" <— are considered unnecessary since "not" is already there.
In the given sentence, "The physician started to perform the operation, but the patient was not yet completely under anesthesia," there is no incorrect word or phrase.
However, if we consider the sentence from a grammatical standpoint, there is a difference in verb tense usage. The verbs "started" and "was" are in different tenses: "started" is in the past tense, while "was" is in the past progressive tense. Although this difference in tense usage is grammatically correct, it does create a slight inconsistency in the sentence.
To resolve this inconsistency, you could modify the sentence to use the same tense throughout. Here's an example: "The physician began to perform the operation, but the patient was not yet completely under anesthesia." In this revised sentence, both verbs "began" and "was" are in the past tense, which maintains consistency.