It is always those forgive first achieve more happiness.
A. 不填; that
B. who; and
C. who; that
D. that; but
网友回答
A. 不填; that
B. who; and
(答案→)C. who; that
D. that; but
解析：考查强调句型和定语从句。定语从句Who forgive first修饰先行词those，who 在句中做主语.第二空的that与it is构成强调句型的基本结构。句意：正是那些先原谅别人的人获得了更多的幸福。