=>
21. That news should be announced as soon as possible.
-> bị động should be V3/ed
22. It was announced that the workshop was delayed about 2 hours because of mechanical problems.
-> chủ động : People/they/... + said/announced that S V
-> bị động : It was said/announced that S V
23. This house and these cars are going to be painted for Christmas Day by the Greens.
-> bị động is/am/are going to be V3/ed
24. The pollution problems have been discussed by the students since last week.
-> bị động HTHT have/has been V3/ed
25. I will get a new dress made by the dressmaker.
-> bị động get sth V3/ed
26. The needles are kept in acupoints for about twenty minutes.
-> bị động HTĐ is/am/are V3/ed

21. That news should be announced as soon as possible.
→ should be + V3/ed
22. It was announced that the workshop was delayed about 2 hours because of mechanical problems.
→ It was said/announced + that + S + V
23. This house and these cars are going to be painted for Christmas Day by the Greens.
→ is/am/are + going to be + V3/ed
24. The pollution problems have been discussed by the students since last week.
→ have/has been + V3/ed
25. I will get a new dress made by the dressmaker.
→ get sth + V3/ed
26. The needles are kept in acupoints for about twenty minutes.
→ is/am/are + V3/ed

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@nam