The days we spent 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：考查定语从句和形容词用法。第一空考查了定语从句，关系代词that指代先行词the days作为定语从句中spend的宾语。第二空考查了形容词的用法，形容词easy/difficult/hard后面使用不定式的主动形式表示被动的含义。句意：我们一起在农场中度过的日子不容易被忘记。故C正确。