Grammar Suggestion

Cute572

 Thanks Mr. Wordy!

1. In this version we are using their instead of its. Because rays are plural right ?

2. Ok i noted these points and also the sentence.

And Mr. Wordy i always got confuse between these prepositions : On, Over , At 

Could you please give some suggestions so that i could remember its proper usage.

1. Yes.

2. I'm struggling to think of any worthwhile general rules that I can offer regarding the use of these prepositions. Any general statements that I might make are likely to have so many exceptions as to be virtually useless. You can look up the core meanings of the prepositions in a dictionary, and that should give you a rough idea of the range of meanings they can take. But it probably won't help much with the hundreds (or thousands) of special cases and idiomatic uses, many of which have no obvious logic to them. Explaining all of these -- or even just the common ones -- would be a major project and would fill many, many pages.