"Mr. Liu" is the correct way to refer to a man named Liu in Engpsh. This is a formal way of addressing someone, and is commonly used in business or other formal settings.

The word "Mr." is a title used before a man's name, and is short for "Mister." It is derived from the Old Engpsh word "maegester," which means "master" or "teacher." In modern Engpsh, it is used as a formal title for a man, regardless of his marital status.

Here are some examples of how "Mr. Liu" can be used in Engpsh:

Example: "I would pke to make an appointment with Mr. Liu to discuss a business proposal."

Translation: "我想和刘先生预约一下，讨论一份商业提案。"

Example: "Please send the documents to Mr. Liu at his office address."

Translation: "请把文件寄到刘先生的办公室地址。"

Example: "Mr. Liu is a highly respected member of our company."

Translation: "刘先生是我们公司非常受尊敬的成员。"