1.The doctor did all ____ to save the wounded boy填he could ,在这里是不是all 后面的that 可以省略呢来引导定从?2.Has ____ must be done been done?a.all b.all that c.that d.it这里为什么选B?如果修饰先行词 all的话,为什

1.The doctor did all ____ to save the wounded boy填he could ,在这里是不是all 后面的that 可以省略呢来引导定从?2.Has ____ must be done been done?a.all b.all that c.that d.it这里为什么选B?如果修饰先行词 all的话,为什
1.The doctor did all ____ to save the wounded boy
填he could ,在这里是不是all 后面的that 可以省略呢来引导定从?
2.Has ____ must be done been done?
a.all b.all that c.that d.it
这里为什么选B?如果修饰先行词 all的话,为什么不能像第一题那样省略 that 这2题区别在哪?第2题其他选项错在哪?

1.The doctor did all ____ to save the wounded boy填he could ,在这里是不是all 后面的that 可以省略呢来引导定从?2.Has ____ must be done been done?a.all b.all that c.that d.it这里为什么选B?如果修饰先行词 all的话,为什
1、先看两题all的区别,1句中all做整个句子的宾语,它的前面的谓语动词是do；而2句中的all做整个句子的主语.
2、尽管先行词都是all,但1句中that是作从句的宾语（he could do that）,而2句中that是作从句的主语（that must be done）.理解了这一点也许你就明白了,因为引导词that等只有在从句中作宾语时才可以省略.
3、如此看来,2句中a后that不能省,c句整个主句缺少主语,d句不通.