1. 1) Past Continuous in Passive Voice, отправлялось (письмо, например)
2) Past Simple in Passive Voice, были отправлены.
2. 1) When he came the guests had been entertained by Natalie.
2) She is promised a new toy tomorrow.
3. 1) A letter has just been dictated by Mr. Brown to his secretary.
2) His suitcase is being packed now.
3) The contract will has been signed by tomorrow.