1. I have to exchange our airline tickets.
2. I had to exchange our airline tickets.
3. I'll have to exchange our airline tickets.
4. I have to exchange our airline tickets today between 2:00 and 3:00.
5. The police must gain public trust.
6. Yesterday we had to go on a business trip.
7. The plane was supposed to take off exactly on schedule.
8. We have to spend the night at the airport.
9. No one can know my secret.
10. No one was supposed to know my secret.
11. We were supposed to meet last night at noon, but we didn't.
12. Members of the British Parliament are prohibited from entering the House in armour.
13. Our colleague does not need to speak at tomorrow's conference.
14. Our colleague was to prepare a report, but he does not have to speak at the negotiations.
15. Our partners should inform us of their decision tomorrow.
(НЕ ЗНАЮ КАКОЙ ВАМ НУЖНО ЗАЛОГ УПОТРЕБЛЯТЬ! Написала и в действительном и в страдательном. Сам выбирай!)
2) But for the lack of time (but if it had not been for the lack of time), the paper would have been translated into two working languages of the conference ИЛИ they would have translated the paper into two working languages of the conference.
3) But for your recommendation (but if it hadn't been for your recommendation), I wouldn't have known how to deliver the paper properly ИЛИ the paper wouldn't have been delivered properly.
4) But for his carelessness (but if it hadn't been for his carelessness), the application form wouldn't have been lost ИЛИ he would not have lost the application form.
5) But for sponsors (but if it hadn't been for sponsors), we would have failed to pay for the computer facilities ИЛИ the computer facilities wouldn't have been paid for.
6) But for shortage of funds (but if it hadn't been for shortage of funds), the conference would have been called twice a year ИЛИ they would have called the conference twice a year.
7) But for the efficient work of the editorial committee (but if it hadn't been for the efficient work of the editorial committee), the abstracts of papers wouldn't have been published in time. ИЛИ they would have failed to publish the abstracts of papers in time.
8) But for the taxi (but if it hadn't been for the taxi), I would have been late for the opening ceremony of the conference.