This box is the same heavy as that one.
= This box is as heavy as that one.
在相同的情形下,两个应该可以通用.
再问： she sings as well as her sister does? 我们老师说的是the same as后不可以加句子，her sister does是句子，我不懂 题目是这样的。she sings well，her sister sings well ，too（合成一句话） she sings — — —her sister — 我想写的是she sings the same as her sister well
再答： 你的写法肯定不合英语规范。 单独说，the same太笼统，不知与……如何同样地？同样地快/慢/糟糕……？所以，必须说： the same + well/ fast/ slowly / badly + as + sb (does/ do/ did). You can say, She sings the same well as her sister (does). 后半部分可以是：...as her sister does = sings. 这是个有主语(her sister) + 谓语（助动词) does= sings的方式状语从句。 也可以说：...as her sister.省去了谓语动词部分，则只是一个方式短语。 两者除了句子结构不同外，在语义上没有任何区别。
