What is one characteristic of a complex sentence?

In the odyssey which is most effective paraphrase of the passage

Mary is reading a book that has 135 pages. she can read 18 pages in an hour. if she takes h hours to finish reading the book, the equation that can be used to find the value of h is

Phosgene is a chemical agent that is formed by decomposition of chlorinated hydrocarbon solvents by ultraviolet radiation.