Use percentage to describe a portion in relationship to a whole. We have an 80 percent retention rate. The office receives a large percentage of inquiries from high school students in Connecticut. Quotations make a publication much more lively. I moved to Jamaica Plain after my salary adjustment was approved.
Stationery refers to writing paper and envelopes.
While Nero fiddled, Rome burned. Use which or that when referring to animals, things, concepts, or groups. She wondered why my mother, who is of Vietnamese descent, has blond hair. The new computer parts, which were just delivered, are the wrong size. Verbs that accompany them must agree in number.