【正文】
have been 19. Do you have any idea _______ is actually going on in the classroom? A. that B. what C. as D. which 20. here is much chance ________ Bill will recover from his injury in time for the race. A. that B. which C. until D. if 21. Nobody believed his reason for being absent from the class ______ he had to meet his uncle attheairport. A. why B. that C. where D. because problem _______many children have _____ out of school is getting more and more serious. A. that; dropped B. which; got C. of; fallen D. as; run , as well as his parents _____to the party. A. has invited B. are invited C. has been invited D. have been invited half of the population _____working in the city and the number of workers_________ increasing