What part of the letter needs revision in order to be appropriate for a formal letter

Choose one of the topics below and use all five sentence patterns in a composition of at least 100 words. return to the lessons "patterns: inverted, compound parts, s/v/do" and "patterns: s/lv/pn, s/lv/pa, s/v/io/do" if you need to review the sentence patterns. you will be graded based on whether all five sentence patterns are present in your work. suggestions for topics: a. what if the sun exploded? b. what if every family owned a helicopter? c. what if each year were six months long instead of twelve? d. what if you were the president of the united states?