Based on the following circumstance, decide if the sentence…
Based on the following circumstance, decide if the sentence in Chinese is correct or not. You point to a person standing about thirty feet away, and say: 这个人是我的老师， 他是北京人。 You introduce to your friend a boy standing next to you and say: 这是白先生的儿子。 You point to a girl next to you, and say: 他是我的妹妹。 You are holding a family photo in your hand, and say: 这是我爸爸， 这是我妈妈。