It was a great for him to be pleasant to people he didn't like.
A. attempt
B. trouble
C. power
D. effort
网友回答
A. attempt
B. trouble
C. power
(答案→)D. effort
解析： effort （作可数名词用）（=vigorous attempt）努力的尝试：Does it require a great effort of will to give up smoking? （戒烟需要坚强的毅力吗？）