Question

the girl wearing a red sweater is my sister.

为什么前面没有be动词还加ing？

Answer 1

wearing a red sweater 分词作定语修饰the girl 本句主语是the girl , is系动词 my sister.是表语 此句亦可改为The gilr who is wearing a red sweater is my sister , who is wearing a red sweater是定语从句修饰The gilr

Answer 2

wearing a red sweater 现在分词短语作定语=who is wearing a red sweater