was playing是什么時(shí)態(tài)

　　In the distance a band was playing.

　　遠(yuǎn)處有個(gè)樂隊(duì)在演奏。

　　A tango was playing on the jukebox.

　　自動(dòng)點(diǎn)唱機(jī)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。