选Bleft
这样把原句变形一下：the teacher said"can't you finish it by yourself?" left to the copied homework.
后半句left to the copied homework 是做状语修饰 the teacher said"can't you finish it by yourself?" 这个动作 其中leave sth. tosb.\sth. 是把某物留给某人、物的意思变形之后有 do sth. leave to sb.
因为动作发生在过去 所以就把leave 变成left 就行啦~