The days we spend together on the farm are not easy .
A. when; to forget
B. which; to be forgotten
C. that; to forget
D. /; to be forgotten
网友回答
A. when; to forget
B. which; to be forgotten
(答案→)C. that; to forget
D. /; to be forgotten
解析：考查定语从句。第一个空要用关系代词引导定语从句修饰days，并作spent的宾语；第二个空放在easy后面要用不定式的主动形式。句意：我们在农场一起度过的日子永难忘记。故C正确。