backstroke /ˈbækˌstrəʊk/

• 1. 

  N-UNCOUNT Backstroke is a swimming stroke that you do lying on your back. 仰泳 [also 'the' N]

  例：

  "I see you know how to swim very well," she said, watching him do the backstroke.

  “看来你很会游泳啊”，她一边说一边看他仰泳。