1. When you think of the innumerable birds that one sees flying about,
    你可以想象出天上有看得见的飞来飞去、数不清的鸟，

2. There are innumerable constellations in the sky.
    天空中有数不清的星座。

3. You can think of the innumerable birds.
    你可以想象那些数不清的鸟,