When Marx was in London, he  __   read at the library for hours.

—When can I come here for the photos? I really need them tomorrow afternoon. —They _______ be ready by 12:00. 

Passengers _____ fasten their seat belts immediately after taking their seats. The belts should remain buckled during the flight whether or not the “fasten seat belt” light is on.

____ I fill in the application form right now, sir? No, you needn’t. You can complete it this afternoon.

They       have got lost, or had an accident.