Rewriting the second sentence by using a cohesive device: A: How

Rewriting the second sentence by using a cohesive device: A: How do you know that he's retiring soon? B: He told me that he's retiring soon.
【正确答案】：He told me so.
【题目解析】：根据句意：你是怎么知道他快退休的呢？ 是他告诉我的。第二句的回答that he is retiring soon与问句的宾语从句重复，为避免重复，可用so表示如此。