单项选择题
A．The woman is the manager’s secretary. B．The man found himself in a wrong place. C．The man is the manager’s business associate. D．The woman was putting up a sign on the wall.
A．students can switch to different discussions at any point B．students can download relevant critical comments C．professors can join in students’ online discussions D．professors can give prompt feedback to students’ homework
A．share his learning experience with the best and brightest thinkers B．participate in discussions with classmates and Facebook friends C．vote for the best learners democratically D．store information on the cloud