The whole family were worried about Jane because no one was aware ___she had gone．

A．that where

B．of the place which

C．of what

D．of where

如图是实验室中模拟炼铁的实验装置，完成下列问题    

(1)实验过程中先进行的是____。（填“加热”或“通一氧化碳”）    

(2)写出A中反应的化学方程式：____________    

(3)B中观察到的现象是________，B中反应的化学方程式是____。    

(4)该装置的不足之处是________。