Translation of septuagésimo

We do not see the spider eating the moth, we only see a yellow spider sitting on a red flower holding a brown moth. But we know what will occur: There will be a cruel and nasty act of the nature.
Please write me from your home as soon as your are back. My Spanish is better than that of most Americans, but my English is worse than that of most people here. It is a strange position that I am in.
Sorry for bothering you with so many questions. You are going to be my first online language course. The more I trust you and your website, the more I will use it and recommend it...No problem...