他被邀请担任这个项目的顾问。

He was asked to ___act ___as an advisor on the project.

我有经验为你们的赛车俱乐部担任裁判。

I have the experience to ___act ___as an official for your racing club.

当医生不在时，一位资深护士不得不临时担任医生。

When the doctor was away, a senior nurse had to ___act ___as the temporary physician.