两个句子的疑惑

第一个句子：
By using both ears one can tell the direction _______ a sound comes.
A.in which
B.from which
C.with which
D.through which
定语从句，in the direction为固定用法，如果不用介词加副词的形式，此题应填where,相当于in which.
第2句话：
I saw a woman running toward me in the dark. before I could recognise who she was, she had run back in the directions ____ she had come.
A. of which
B.by which
C.in which
D.from which
这句in the direction 完整，不需补充，实际上缺少介词的是come,一般为from,所以选from which

in the direction of 才是一个词组，意思为朝。。的方向.也可以理解为通过...的手段或者方法，途径等 在此句里dirction = way
第二个是DIRECTION的定语从句 she had come from the direction

两个都是 from which。

FROM WHICH