请问They were worried about sth.中是were做系动词,worried作表语,about sth是介词短语做状语吗?

问题描述:

请问They were worried about sth.中是were做系动词,worried作表语,about sth是介词短语做状语吗?
还是were 做助动词worried做谓语about sth做状语?

worried是形容词化的过去分词,当作形容词使用,在句子中做表语;
be worried about 是固定短语,sth在句子中做宾语