Why did he use “did” in this sentence? Is it grammatically needed?
Native speaker’s answer
Rebecca
"Did" in this context is used for emphasis to reaffirm a statement. It puts the sentence in a question-like form with "did" to give it emphasis. It is necessary in this context to use "did" unless the sentence is reworded. Ex: Did I see her? Yes I did. Ex: Not only did I watch the performance but I filmed it too!