自主高效练八年级英语外研版评议教辅
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20. I have made up my mind to take a break from social media.（改为同义句）
I have
decided to
take a break from social media.
答案：decided to
解析：“make up my mind”意为“下定决心”，其同义短语为“decide to”，原句时态为现在完成时，所以此处用“decided to”。
21. My grandparents have already been to Sanya.（改为否定句）
______
答案：My grandparents haven't been to Sanya yet.
解析：现在完成时的否定句是在助动词“have/has”后加“not”，“already”在否定句中通常改为“yet”，放在句末。原句主语是“My grandparents”，助动词用“have”，所以否定句为“My grandparents haven't been to Sanya yet.”。
22. People have improved air quality in the cities by driving less.（改为一般疑问句）
______
答案：Have people improved air quality in the cities by driving less?
解析：现在完成时的一般疑问句是将助动词“have/has”提到主语之前，原句主语是“People”，助动词用“have”，所以一般疑问句为“Have people improved air quality in the cities by driving less?”。
23. There will be life on that planet.（用现在完成时改写句子）
______
答案：There has been life on that planet.
解析：现在完成时的结构为“have/has+过去分词”，“there be”句型的现在完成时为“There have/has been...”，“life”是不可数名词，所以用“has been”，改写后的句子为“There has been life on that planet.”。
24. writer，David，a，has become，successful（.）（连词成句）
______
答案：David has become a successful writer.
解析：根据所给单词，“David”是主语，“has become”是谓语，“a successful writer”是宾语，所以连成的句子为“David has become a successful writer.”。
