1.everyone(加上who)ishere,includingchildrenandoldpeople,to(to去掉)goesinforsports前面加上who构成定语从句修饰everyone,后面去掉to是因为后面
是谓语,不定式不作谓语.这是一主从复合句,everyonegoesinforsports是主句,其它是从句.整个句子意思是:这的每个人包括老人和孩子都喜欢运动.
2.thebeautifulladyinblueinfrontofthesedancers(加上was)singinganEnglishsongwhenTomcamein.因后面有从句,当,时所以前用进行时作谓语.如不加was.只有singing不能作谓语.
3.nothingisdiffcultintheworld,isn't(isn't-is)it.因为前面为否定句,后面要用肯定式.这是反意问句的构成规则.