Question

【題目】People have changed their ways of life to protect the environment. (改為被動語態)

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

Answer 1

【答案】have been

【解析】

句意：為了保護環境，人們改變了生活方式。

將原句改為被動語態，主語people's ways of life表復數概念，且時態為現在完成時，故此處應為現在完成時的被動語態have been done。故答案為have been。