was playing是什么時態(tài)

　　In the distance a band was playing.

　　遠處有個樂隊在演奏。

　　A tango was playing on the jukebox.

　　自動點唱機播放著一首探戈舞曲。

　　He was playing chess with his uncle.

　　他在和伯父下國際象棋。