有错
My sister told him who she was waiting for?
wait for 等候某人,后跟宾语 who
不明白的再问哟,请及时采纳,多谢!什么叫脑袋卡，这就是其中的一个表现，作为宾语从句，那么可以改为My sister told him for which she was waiting ?这样可以吗？which 改为： for whom