对香港繁荣稳定起重要作用的铁路是[ ]
A．京沪线
B．京九线
C．广九线
D．陇海线
答案：B
It was not until early this morning _______ my father came back from work, which surprised us.
A．when
B．where
C．that
D．who
下列选项中，（）不属于一次能源。
A.石油
B.天然气
C.煤炭
D.焦炭
