我国现存最早的天象观测建筑为( )。
A．北京古观象台
B．西安古观象台
C．河南登封古观象台
D．河南洛阳古观象台
E．河南开封古观象台
参考答案：A,C
It is reported that nowadays more and more children _____ playing computer games.
A．are addicted to
B．are addicted with
C．addiction to
D．addiction with
PAPI灯的作用有哪些？
