AuntHarrietdiscoveredthattherewerepilesofemptywinebottlesofallshapesandsizeneatlystackedinwhathadoncebeenBessie'swardrobe.这句话中what是什么用法

Question

Aunt Harriet discovered that there were piles of empty wine bottles of all shapes and size
neatly stacked in what had once been Bessie's wardrobe.这句话中what是什么用法

Answer 1

in 是介词,所以what had once been Bessie's wardrobe是介词in的宾语从句.what == sth that.
又如：
He lives in / comes from \ what is Shanghai,the biggest city in China.
what== the place that / which.
这里,in和from都是介词,所以what is Shanghai,the biggest city in China是宾语从句.