Question

2. Mr Li has some trouble sleeping,so drinking a glass of milk before going to bed every night is his common       (惯例) .

Answer 1

2. practice考查名词。practice练习，做法。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惯例。