1．In America people only wear nightgowns to sleep in.这里面的介词in 是说 wear in nightgowns么？所以这个in是必需的？
2. The word "Cartoon"came form Italian , referring to the picture drawn in preparation before an actual drawing on the wall
was started. ”referring”引导的后面的句子做什么成分？
參考答案:1. in是表示穿着前面那个nightgowns.是必须的
2. 后面不是句子,而是一个介词短语.