they went there to watch the iron tower___ a.to be erected b.be e_英语解答

they went there to watch the iron tower___ a.to be erected b.be erected

人气：433 ℃　时间：2020-06-22 05:58:05

解答

B
watch /hear /see sb .do /doing
watch /hear /see sth,done /being done
没有不定式的形式.