17.In big parties, how do people get to know each other?

　　在大型聚会上,人们怎样相识?

　　By making self-introduction.

　　通过自我介绍。

　　18.When making self-introduction, how many minutes should it take?

　　做自我介绍时，多长时间为宜？

　　Half a minute, no more than one minute.

　　半分钟，不能超过一分钟。