What is the reference of the moon hidden in the clouds? What is the reference for dark clouds to cover the moon?

(1) The moon is hidden in the clouds, and the object of study is the moon. The moon is hidden in the cloud, which means that the moon is moving and the position between the cloud and the moon has changed, so the cloud is chosen as the reference.

(2) Dark clouds cover the moon, and the object of study is dark clouds, which cover the moon, indicating that the dark clouds are moving and the position between the dark clouds and the moon has changed, so the moon is chosen as a reference.