问题
选择题
Mr.Li has some trouble sleeping, so drinking a glass of milk before going to bed every night is his common
A．practice
B．knowledge
C．experience
D．duty
答案
答案：A
题目分析：考查名词辨析：A、practice练习，做法，B、knowledge知识，C、experience经验，D、duty责任，值日，句意：李先生睡觉有困难，所以每天晚上睡觉前喝杯牛奶是他的惯例。Commom practice是“惯例”，选A。