Замените следующие действительные обороты страдательными:
1. Who has written this article?
2. The workers are unloading the steamer.
3. The director has just signed the letter.
4. The customs officer is counting the cases.
5. When he entered the room, the legal adviser was checking the contract.
6. The buyers will insure the cargo with "Gosstrakh".
7. As the buyers had not opened a letter of credit, we could not ship the goods.

1. By whom was this article written? [or: Who(m) was this article written by?]
2. The steamer is being unloaded by the workers.
3. The letter has just been signed by the director.
4. The cases are being counted by the customs officer.
5. When he entered the room the contract was being checked by the legal adviser.
6. The cargo will be insured by the buyers with "Gosstrakh".
7. As a letter of credit had not been opened by the buyers, the goods could not be shipped by us.