干熄焦余热锅炉省煤器安置在锅炉的（）。
A.上部
B.中部
C.底部
D.外部
参考答案：C
It took me a long time before I was able to fully appreciate what they ______ for me.
A．had done
B．did
C．would do
D．were doing
专题分析
