Question

The pretty lady ______you told me the other day turned out to be a thief ,

A.who B.whom C.about whom D.with whom
为什么不选B，而是C
tell sb about sth tell sb sth 不是都可以吗？

Answer 1

句意：那天你跟我提到的漂亮女士原来是个贼。
句子的主语是the pretty lady ，后面的从句一直到the other day都是后置定语来修饰the pretty lady的，这里的搭配并不是tell sb about sth 或者tell sb sth，因为这两个搭配里面的tell是告诉,告知的意思，而句子中的tell是提到，讲述的意思，有区别。
再举个例子你就明白了，the story you told me yesterday is very interesting.(you tell me a story)

Answer 2

这个句子还可以这样说：You told me about the pretty lady the other day, and she turned out to be a thief.所以用到的是tell sb about sb/sth 这个短语。意思是"告诉某人有关某人或某事的事”