Question

【題目】People have changed their ways of life to protect the environment. (改為被動(dòng)語(yǔ)態(tài))

People's ways of life ________ changed to protect the environment.

Answer 1

【答案】have been

【解析】

句意：為了保護(hù)環(huán)境，人們改變了生活方式。

將原句改為被動(dòng)語(yǔ)態(tài)，主語(yǔ)people's ways of life表復(fù)數(shù)概念，且時(shí)態(tài)為現(xiàn)在完成時(shí)，故此處應(yīng)為現(xiàn)在完成時(shí)的被動(dòng)語(yǔ)態(tài)have been done。故答案為have been。