Instructors answer student questions by e-mail, instant message, phone or fax.
教师用电邮、即时讯息、电话或传真回答学生的问题。
《柯林斯英汉双解大词典》
2
Conceptually, e-commerce does not differ from well-known commercial offerings such as banking by phone, "mail order" catalogs, or sending a purchase order to supplier via fax.