Don’t be angry with the little boy! He broke the window .
A. on purpose
B. at once
C. in surprise
D. by accident
网友回答
A. on purpose
B. at once
C. in surprise
(答案→)D. by accident
解析：句意，不要和这个小男孩生气！他只是偶然地打破了玻璃。on purpose 故意地 at once 立刻 in surprise 惊奇地 by accident 偶然地，根据题意，故选D。