Open the brackets the correct tense indefinite/past perfect. write down the sentencesin your exercise book + указать время и объяснить почему вы его вставили

1. when the delegation(to arrive) at the conference, the journalists already(to take) their places in the hall. 2. when the secretary(to get) fax, the boss(to go) home. 3. the chinese(to inventy) paper earlier than the europeans. 4. we(to write) the article when mike(to bring) new information 5. the city(to learn) about a new exhibition from morning newspapers. 6. l (to read) the book before i(to watch) the film. 7. she(to understand) that she never(to see) such a beautiful picture before.

Случаи употребления глагола Ought to
Для выражения долженствования, совета, рекомендации.
Для выражения вероятности чего-либо.

Случаи употребления глагола Have to
Для выражения необходимости совершения действия.
Для выражения вероятности чего-либо (чаще употребляется в американском английском).

Случаи употребления глагола Must
Для выражения необходимости совершения действия.
Для выражения настоятельного совета или приказания как самому себе, так и другим.
Для выражения предположения, что что-то может быть правдоподобным или вероятным.

Случаи употребления глагола Should
Для выражения необходимости, совета, рекомендации.
Для выражения вероятности чего-либо.

1. When will the first 20 containers be delivered? - The first 20 containers will be delivered end June after full deposit received on time.
2. What need THE BUYER to do when the containers had been produced and completed in fulfilling this contract? - When the containers had been produced and completed in fulfilling this contract, THE BUYER need to receive the tank or to provide information for THE SELLER to deliver the containers to her specified location within 30 days from day of completion. 
3. What shall be treated as refusal to receive the containers? - Postponement of delivery date beyond the 30 days’ grace period by THE BUYER, despite of all reasons other than for reason of quality failure of the containers, shall be treated as refusal to receive the containers.
4. What do the Seller and the Manufacturer warrant? - The Seller and the Manufacturer warrant that each container will be built to the Specification and requirements of the Contract, and will be free from defect in workmanship, materials and design.
5.Which responsibility is it to cross-reference and confirm the agreed specification? -  It is the BUYER or USER’S responsibility to cross-reference and confirm the agreed specification is suitable for their intended cargo and usage.
6. What should the BUYER always directly seek? - The BUYER should always directly seek the relevant SUPPLIER for any Technical or Sales support for the Component.