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?