roles
If you have a role in a situation or in society, you have a particular position and function in it.
Until now scientists had very little clear evidence about the drug's role in preventing more serious effects of infection.
到目前为止,科学家们几乎没有确切的证据能够证明该药在预防更严重的感染方面会发挥作用。
Both sides have roles to play.
双方都有作用可发挥。
A role is one of the characters that an actor or singer can play in a film, play, or opera.
She has just landed the lead role in their latest production.
她刚刚获得了在他们的最新作品中出演女主角的机会。