【例1】 If nothing________(do), the oceans will turn into fish deserts.
【解析】 nothing 与 do 之间为被动关系，故用被动语态形式。主句用一般将来时，条件状语从句用一般现在时。
【答案】 is done
【例2】 —So what is the procedure?
—All the applicants________(interviewed) before a final decision is made by the authority.
【解析】 All the applicants 与 interview 之间为被动关系，故用被动语态形式，根据问句时态可知，用一般现在时的被动语态。
【答案】 are interviewed
【例3】 We are confident that the environment ________(improve) by our further efforts to reduce pollution.
【解析】 句意：我们很自信，通过我们进一步实施减轻环境污染的措施，环境将会被改善。从句中有 further，所以用将来时的被动语态。
【答案】 will be improved
