When we were dancing the rain in that december因为用了were,就知道这是过去式,那为什么要用dancing加ing呢?求语法

They were singing while we were dancing. When we were dancing the rain in that december因为用了were,就知道这是过去式,那为什么要用dancing加ing呢?求语法 英语翻译When we were in middle school we all had to take a dancing unit in gym.3Q! They were singing whenwe were dancing可以用when when the phone rang,we were singing and dancing对划线部分提问 划线处是,前面的 when we were young 连词成句：she,were,in,you,when,came,dancing. When We Were Together 歌词 When We Were Beautiful 歌词 When We Were Beautiful 歌词 WHEN WE WERE ORPHANS怎么样 some girls were singing when others were dancing.这句话哪里错了 They were singing while we were dancing.怎么读,我想知道它们的发音 They were singing while we were dancing这句话可以用while吗 They were dancing when they heard the bell的问句是什么? one day when we were young one day when we were young演唱者 When We Were Beautiful (Live) 歌词