如动词为 make, see, hear, watch 等,后接宾语补足语为不带“to”不定式时,变被动语态时要加上“to” 。 I saw him fall off the tree. He was seen to fall off the tree. 6. "be + 过去分词" 并非都是被动语态,系动词 be, feel, seem,look,等词后面的过去分词已转化...