If we had known we were so tired, we would not have come to your house. Is that statement a complex sentence.

you have to tell us what you're talking about or it's impossible to answer.

- "the basic difference between keywords and subjects is that subjects (or "subject headings") have been predetermined, while keywords have not. a keyword is an easy place to start because you can use any word that seems to fit your search; this is called "natural language" searching."

there is no passage.