单项选择题
Please contact Jen Davis in the HR Department if you have any questions regarding the new overtime and vacation______.（）
A．methodsB．policiesC．reactionsD．behaviors
单项选择题 (144)（）
单项选择题 Johnson’s paper ______three processes for generating hydrogen in fuel cells.（）
单项选择题 Portable, affordable, and stylish: personal listening devices have never been a more popular______.（）
