Chuyển câu sang bị động 37. You ought to water these plants once a week. 38. Everyone is sure to check the documents monthly. 9. The boy screamed while the dentist was pulling out one of his teeth. 40. The child knew that they were praising her. 41. No one has opened that box for the past hundred years. 1559

37. You ought to water these plants once a week.

⇒These plants ought to be watered once a week.

38. Everyone is sure to check the documents monthly.

⇒The documents is sured to check monthly.

39. The boy screamed while the dentist was pulling out one of his teeth.

⇒The boy screamed while one of his teeth was being pulled out by the dentist.

40. The child knew that they were praising her.

⇒They was known that were praising her.

41. No one has opened that box for the past hundred years 1559.

⇒This box hasn't been opened for a hundred years 1559.