孙老师，有道题请教一下，They are so alike that we can€t tell ____ is which. A.what B.that C.which D.how 我的问题是which 在名词性从句中不是只能做名词的定语吗？怎么在这还能做主语和表语啊？

which也能引导名词性从句。Do you know which he likes best?

你好，我应该怎学英语