When paying for a taxi, he never looks at his wallet –just takes out one note and hands it over.
A. by accident
B. on occasion
C. at random
D. on average
网友回答
A. by accident
B. on occasion
(答案→)C. at random
D. on average
解析： 考查固定定语：by accident 偶然地，on occasion 偶尔， at random随便的，on average 平均的，句意：当给出租车付款的时候，他根本不看钱包，只是随便拿出一张支票递过去。故选C。