Sending E-mails to ProfessorsOne student skipped class and then sent the professor an e-mail (51) for copies of her teaching notes. Another (52) that she was late for a Monday class because she was recovering from drinking too much at a wild weekend party. At colleges and universities in the US, e-mail has made professors more approachable(平易近人 ). But many say it has made them too accessible, (53) boundaries that traditionally kept students at a healthy distance. These days, professors say, students seem to view them as available (54) the clock, sending a steady stream of informal e-mails. "The tone that they take in e-mails is pretty astounding(令人吃惊的)." said Michael Kessler, an assistant dean at Georgetown University. "They’ll (55) you to help: ’I need to know this. ’" "There’s a fine (56) between meeting their needs and at the same time maintaining a level of legitimacy (正统性) as an (57) who is in charge. " Christopher Dede, a professor at the Harvard Graduate School of Education, said (58) show that students no longer defer to (听从) their professors, perhaps because they realize that professors’ (59) could rapidly become outdated. "The deference was driven by the notion (60) that professors were all-knowing sources of deep knowledge. " Dede said, and that notion has weakened (61) . For junior faculty members, e-mails bring new tension into their work, some say, as they struggle with how to (62) . Their job prospects, they realize, may rest in part on student evaluations of their accessibility. College students say e-mail makes (63) easier to ask questions and helps them learn. But they seem unaware that what they write in e-mails could have negative effects on (64) them, said Alexandra Lahav, and associate professor of Law at the University of Connecticut. She recalled an e-mail message from a student saying that he planned to miss class so he could play with his son. Professor Lahav did not respond. "Such e-mails can have consequences. " she said. "Students don’t understand that (65) they say in e-mail can make them seem unprofessional, and could result in a bad recommendation. " 59（）

A. technology
B. expertise
C. science
D. imagination