正在进行时为singing，例如：
1.Her singing career was all washed up by the time she was 27.她到27岁时歌唱生涯就告终了。
2.Birds were already singing in the garden.小鸟已经在花园里开始歌唱了。
3.She has a good singing voice.她有一副很好的歌喉。
