问题补充：
It was a great for him to be pleasant to people he didn like.
A. attempt
B. trouble
C. power
D. effort
答案：
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？）
