Welcome to the unit 
1. Everyone agrees that laughter is good for you. (page 1)  每个人都认为笑对身体有好处。
laughter  
n. [U] the act or sound of laughing 笑;笑声;笑的样子
She roared with laughter (= laughed very loudly).
As we approached the hall we could hear the sound of laughter.
    常用搭配:burst into laughter 爆发出一阵笑声
              roar with laughter  放声大笑