active singing point的用法和样例：
- This paper introduces a coordinate measurment method of cros- sing point between the optical axis of its lens and CCD sensor using a XC-77CE CCD camera as an example.
- A blackbird nosed up into the sky, singing.
- I want you to put more heart into your singing.
- He was pleased to get up to the singing of birds.
- The orient has been playing an active role in the world economy.