31. The room is in a terrible mess; it _______ cleaned.
An increased concentration of carbon dioxide and certain other gases in the Earth’s atmosphere ______ global warming.
New York State has passed a law requiring that all legal contracts _____ in simple, understandable English.
When we first met Eliza, she had no manners, but said ______ her head, without thinking.
Some schools, including us, will have to make ______ in agreement with the national soccer reform.
Languages across the world are becoming extinct ______ endangered mammals and four times endangered birds.