Question

They all ran to the window，________they could see________was happening in the street.

A．where；all what                                  B．from where；what

C．which；all                                          D．from which；that

Answer 1

B　from是一个特殊的介词，后接where引导定语从句，意为“从……所在的位置”；what在宾语从句中充当主语。