Put the verbs given in brackets in the necessary form.
1. Cashiers often (to make) mistakes doing a lot of calculations every day.
2. Punched cards (to use) by J. M. Jacquard to program his loom.
3. People greatly (to change) computers lately.
4. During the experiment the machine (to break) down and (must repair).
5. Our programmer (to write) programs for the computer all day long yesterday. 6. He (to finish) his work before 7 o’clock.
7. When the lesson (to be over), we (to switch) the computer off.
8. What idea Charles Babbage (to have)? He (to design) a fully programmable
mechanical computer.
9. We (to use) computers for three hours to solve those mathematical problems. 10. The problems (not to solve) before the necessary
algorithms (to input) into the computer.
Explanation: The verb "make" is used in the present simple tense because it refers to a habitual action that cashiers often do.
2. Punched cards were used by J. M. Jacquard to program his loom.
Explanation: The verb "use" is changed to the past simple tense ("used") because it refers to a past action that J. M. Jacquard did.
3. People have greatly changed computers lately.
Explanation: The verb "change" is used in the present perfect tense ("have changed") to show an action that started in the past and is still relevant to the present.
4. During the experiment, the machine broke down and had to be repaired.
Explanation: The verb "break" is changed to the past simple tense ("broke") because it refers to a past action. The verb "must repair" is changed to the past simple passive voice ("had to be repaired") to show that it was necessary to fix the machine.
5. Our programmer wrote programs for the computer all day long yesterday.
Explanation: The verb "write" is used in the past simple tense because it refers to a specific action that our programmer did yesterday.
6. He finished his work before 7 o'clock.
Explanation: The verb "finish" is used in the past simple tense because it refers to a completed action in the past.
7. When the lesson was over, we switched the computer off.
Explanation: The verbs "be" and "switch" are changed to the past simple tense ("was" and "switched") because they refer to actions that happened in the past.
8. What idea did Charles Babbage have? He designed a fully programmable mechanical computer.
Explanation: The verbs "have" and "design" are changed to the past simple tense ("did have" and "designed") because they refer to actions that happened in the past.
9. We have been using computers for three hours to solve those mathematical problems.
Explanation: The verb "use" is changed to the present perfect continuous tense ("have been using") to show an action that started in the past and is ongoing until now.
10. The problems were not solved before the necessary algorithms were input into the computer.
Explanation: The verb "solve" is changed to the past simple passive voice ("were not solved") to show that the problems were not completed. The verb "input" is changed to the past simple tense ("were input") because it refers to a past action.