Не сообразил, почему бесмысленно вставлены в скобках глаголы не имеющие никакого

Не сообразил, почему бесмысленно вставлены в скобках глаголы не имеющие никакого смысла с общей сущностью предложений? Кто даст подсказку? делаю это задание просто, и не могу понять почему так.

1. Our president (is) to sign the contract with the British firm at 10 o'clock today.
2. We (are) to begin our journey on the 5th of May.
3. Who (was) to meet the representatives of the British firm at Sheremetievo Airport last Saturday?
4. Machinoexport (is) to begin shipment of the goods not later than the 1st of December.
5. The sellers wrote in their letter that the customers (were) to accept the goods in ten days.
6. The secretary said that she (was) to get the materials ready for the talks by 11 o'clock.
7. Our director told us that he (was) to come from abroad in a fortnight.
8. Mr. Camp couldn't wait any more as he (was) to go to the airport in an hour.
9. Mr. Nikolaev said that we (was not) to give the final answer to the firm that day.
10. We found out that the sellers (were not) to begin shipment of their goods in August.