According to the factory safety rules, all accidents _____ be reported to the safety officer.

So many people violate traffic regulations that we ____ put too much emphasis on the importance of traffic safety. 

—Look at the picture on the wall. It ________be David’s.—Yes, his name is on the first page.

—How dangerous it was!—Yes, but for the passer-by’s quick action, the girl ________.

Some aspects of a pilot’s job__________ be boring, and pilots often ________ work at inconvenient hours．