It's necessary to track characters all the way through an opera. If you're dealing with more than one or two characters, it's very easy to forget that the others have lives of their own that feed into the story.
“We had at our disposal the first operational jet, which superseded by at least 150 knots the fastest American and English fighters. This was a unique situation.”
“I want to become a student. I want to read Chinese history and go on a dig.”