A.harvester is a machine _ we harvest crops or a person _ is harvesting.

C

這個句子的主幹

harvester is a machine or a person

harvester是指壹個機器或者壹個人

然後 machine 和a person 後面分別跟壹個限制定語從句

machine 後面用with which 引導我們用機器來收割莊家

person 用who 引導

望采納！