该句型表达的意思是“某人尽最大努力做某事”。everything是先行词，还可用all或what替换。“sb. can”是定语从句，省略了关系代词that，can或could后省略了动词do。不定式to do sth.在句中作目的状语。例如：[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te D S]l6
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Doctors and nurses did all they could to save the patients infected by SARS. 医生和护士尽他们的最大努力挽救感染SARS的病人。[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te i8Q|c 4({
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Peacekeepers will do what they can to keep world peace. 维和人员将竭尽全力来维护世界和平。[文章版权 禁止转载:考试与评价 http://www.trgroup.com.cn/te rzh& RS#o3h`lC?dgFroG]
