serendipitous       
adjective uk/ˌser.ənˈdɪp.ɪ.təs/ us/ˌser.ənˈdɪp.ə.t̬əs/
 偶然的
happening or found by chance
  Reading should be an adventure, a personal experience full of serendipitous surprises.
 A team of researchers has made a serendipitous discovery that could help in the struggle to cure obesity. 一个研究小组取得了一个偶然的发现,可能有助于治疗肥胖症。 
 See: serendipity
 - More examples
 - Serendipitous encounters and experiences have provided me with some good material.
 - He had always wanted to return home to start a company, and the move proved serendipitous.
 - About half of all great discoveries are purely serendipitous.