In a previous lesson we learned how to address young Chinese women 
In general, depending on different situations and the age of the person speaking, there are four ways to address young Chinese men:
帅哥(shuàigē) 
“帅哥(shuàigē)” literally means “handsome man.”
This casual term is common for addressing peers in informal situations.
For instance, if you meet a man who is about your age on the street and you want to ask directions, you can say “帅哥, 你好, 请问…怎么走?(Shuàigē, nǐhǎo, qǐngwèn … zěnmezǒu?) Hey man, how do I get to …, please?”
Certainly, people use the term to show courtesy when starting a conversation, regardless of whether the man is handsome or not.
Examples:  
Wáng Jìng: Shuàigē, zhè shì nǐde shǒujī ma?
小伙子(xiǎohuǒzi) 
“小伙子(xiǎohuǒzi) young man/boy” is always used by the elderly to address young men in informal situations. It also conveys a sense of geniality.
Examples: 
Zhāng Jùn: Yéye, nín qǐng zuò.
大哥(dàgē) 
“大哥(dàgē)” originally refers to the eldest brother in one’s family, but here you can use it to politely address men who are strangers and a little bit older than you. It is also used to refer to men who perform certain services, for example, “快递大哥(kuàidì dàgē)” – courier, “送水大哥(sòngshuǐ dàgē)” – water deliveryman, etc.
Examples:  
Kuàidìdàgē, xièxiènǐ.
先生(xiānsheng) 
“先生(xiānsheng) Mr.” is used in formal situations like dinner parties, meetings, and so on. In such situations, men of all ages can be called “先生(xiānsheng).” If you know their family names, you should typically add the family name in front of “先生(xiānsheng),” as in “李先生(lǐ xiānsheng) Mr. Li,” “张先生(zhāng xiānsheng) Mr. Zhang,” “王先生(wáng xiānsheng) Mr. Wang,” etc.
Examples: 
Lǐ xiānsheng, nínhǎo, zhè shì wǒde míngpiàn.
1. How should you address a young man at a conference?
                  
 
		
		
			 
thank you for your lesson
very nice lesson, thank you
very nice lesson thank you
很有意思
谢谢。
谢谢, 谢谢你
Thanx for this, xiexie ni jiao wo. Wo xian zai dong le.