Question

完成句子

Every year one million tourists visit Stonehenge，which is believed _________(修建)before the Pyramids，about 4,000 years ago．(construct)

Answer 1

答案：to have been constructed
解析：

考查不定式的时态和语态。sth．is believed to do为固定结构，由about 4,000 years ago可知动作已完成。