Exercise 1: Choose the best answer 1.People _____ that the earth is round before. A. did not use to believe B. used to believing C. would not use to believe D. were not used to believe 2.These city girls are used_____ in the field. A. used to work B. to working C. would work D. to work 3.Formerly babies_____ of whooping cough. A. would die B. used to die C. have died D. die 4.Newton_____ scientific books when a boy. A. has read B. read C. had read D. used to read 5.Astronauts_____ in their spaceship, but they frequently work outside now. A. had used to stay B. were staying C. used to stay D. were used to stay