在英语中it is said/supposed/thought/believed/reported/expected...that...句型经常可以换成从句中的主语+is said/supposed/thought/believed/reported/expected/considered...to do的形式,如果that句子的谓语动词已经发生,to do要换成to have done;如果that中的谓语动词正在发生,to do中的do用be doing;其他的基本用to do 就行.这些结果基本翻译为据说/据报道/人们相信/人们料想某人.如：据说他昨天离开了这家工厂了.It is said that he left the factory yesterday.=He(that句中的主语) is said to have left(that后的动作已经发生,所以这里用to have done的形式,) the factory yesterday.
据报道他正在美国读书.It is reported that he is studying in UAS now.=He is repprted to bestudying in USA now.
人们相信他会成功的.It is believed that he will make it some day.=He is believed to make it some day.
所以本句话中替换括号中的句子可以换为It is believed that it was placed.,然后就可以换成it（that句中的主语）is believed to have been placed（that后的谓语动作已经发生,所以不定式后用完成式的形式）.故最佳答案为A
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