have been to是什麼時態

Staff have been retrained to use the new technology.

為使員工學會運用新技術，對他們進行了再培訓。

Several computer engineers have been contracted to the finance department.

有幾位計算機工程師與財務部門簽訂了合同。

I must have been insane to agree to the idea.

我肯定是犯傻了，居然同意了這個想法。

Six theatre companies have been selected to take part in this year's festival.

已選定六個劇團參加今年的`戲劇節。

A number of people have been employed to deal with the backlog of work.

已僱來一些人處理積壓的工作。