这里用 as 或 what 都对

有一读者问：有这样一道选择题：

Things were not_________they seemed to be.

A.as　B.what

答案是A，但what难道不对吗？

as 与 what 都对，只是前者意谓“如、像”，强调一般关系，后者则比较强调具体事物。