1.C 蝴蝶　a type of insect with large often beautiful-colored wings, which develops from a caterpillar
2.C 游手好闲的人，轻浮的人；水性杨花的女人　sb who seems to be only interested in pleasure
3.S 蝶式游泳　a way of swimming on one's front, moving the arms together over one's head while kicking the feet up and down together
4.P （在做重要事情之前等的）忐忑不安　have a nervous feeling before doing sth

　have -lies　情绪紧张
　beautiful ～　美丽的蝴蝶
　social ～　交际花

　Do you think butterfly is a type of insect?　你认为蝴蝶是一种昆虫吗?
　She is a butterfly.　她是一个轻浮的人。
　The butterfly is a kind of water sport.　蝶式游泳是一种水上运动。