If it ____tomorrow, I’d go downtown with my brother.
As a result of destroying the forests, a large _____ of desert _____ covered the land.
David helps his mother with her housework every Saturday for about _____.
Professor Smith, along with his assistants, _____ on the project day and night to meet the deadline.
20.Tell John not to leave the house unless he_____________that the lights .
19.Mrs.Brown is so_________about her housework that few servants Want to work for her.