Tip of the tongue phenomenon refers to the feeling that people can't remember things they are familiar with at ordinary times, but they can't say what they say, especially when they are nervous.
According to the above definition, which of the followings is tip of the tongue phenomenon:
Mr. Jiang always talks freely when chatting. On a blind date, he met a favorite woman. When he was nervous, he became clumsy and didn't know how to talk to each other