空气炮拱炮的操作方式有（）。
A、手动操作；
B、气动操作；
C、远程操作；
D、电动操作。
参考答案：A, B, D
---- Li Yuchun is said to have been invited to 2014 CCTV Spring Festival Show.
---- Really? It’s been a long time ___________ she won the champion in Super Girl in 2005.
A．since
B．that
C．when
D．before
Debenture
