同义句改写小题1:To plant trees every year is necessary for us. ____
同义句改写 小题1:To plant trees every year is necessary for us. ______________for us to plant trees every year. 小题2:Paul left Canada two days ago. Paul __________________Canada since two days ago.
小题1:考查固定句型。不定式可以作主语,it is necessary to do sth做某事很有必要,故填It is necessary。 小题2:考查时态。ago与过去时连用,since+含有过去时的句子,与现在完成时连用。leave是短暂动词,不能与一段时间连用,应该转换为be away,故填has been away from。