某英语语法问题Hewillbeearningonlyhalfasmuchasheusedto跟Hisearningswereonlyhalftheamounttheyusetobe比较,问什么后者句末要加个be呢?

Question

某英语语法问题
He will be earning only half as much as he used to 跟His earnings were only half the amount they use to be比较,问什么后者句末要加个be呢?

Answer 1

1.He will be earning only half as much as he used to 中的as he used to 是方式状语从句,每个从句都是一个完整的句子,用以修饰前一个句子某一部分,有个词组是used to do sth意为过去常常做某事
那么as he used to的完整句 应为as he used to earn,但应为use to比较特殊,为了简便,习惯上把to后面的动词省略了
就像 ：I do as well as he （does）常把does省略了
My book is the same as his (is)常把is省略了
2.His earnings were only half the amount they use to be中的they use to be是定语从句,修饰现行词the amount ,
同时the amount 做they use to be中be的系表结构表语
这个定语从句的完整句为they use to be the amount ,
所以His earnings were only half the amount they use to be的句末要加be
缺了定语从句就缺表语了
我这样解释,你应该理解了吧,不明白可以再问.