请教一下英文科老师
While some Chinese herbs and medicines have active ingredients
and work as _______, many others do not, and their efficacy relies
on the plaebo effect which works when the patient blieves a drug
or treatment is effective.
此题空格答案是promised
请问一下 做何解释及其词性??
小的不才.......

连接词带领的从属子句, 大意是那些药草有活性有效成分且实至名归。as在此是介词, 当作以……的身分解释~promised应该是pp当adj用法~表药效就如同其名确实存在浅见参考看看~

Quasi-relativeronounquasi-relative pronoun