Online distance learning is an instructional system which connec

Online distance learning is an instructional system which connects learners with educational resources．Students work on their own at home,at work,or at school and communicate with faculty and other students by means of e-mail,electronic meetings,videoconferencing,chat rooms,instant messaging and other forms of computer-based communication．There are both advantages and disadvantages to online distance learning. There are many benefits to using online distance learning environments．Online education is available all the time,anywhere and to all people．However,there are weaknesses for some learners．The online learner only has the written text and no other face-to-face hints．This may confuse the learner and cause misunderstanding．While distance learning allows for an openness,it is also difficult because it is done by e-mail messages and writing,and therefore may take more time than face-to-face learning．Sometimes the messages can be overwhelming for many online students. Universities,colleges and schools use online distance learning environments．These are important for students who may be unable to attend classes for various reasons like illnesses or busy everyday schedules．Some learners just want to further their studies at home．They enjoy the convenience of home learning as they take regular programs or enrichment classes. Online courses keep learners very occupied at all hours of the day．There are a great many messages and other online resources to read and respond to．Most learners have regular jobs or attend regular school classes on ground as well．However,the benefits are clear．Online distance learning is becoming very popular．Some online classes have become a profitable business as they replace regular traditional means of learning. With regular means of learning,the learners have to study__.
A、at school
B、on their own
C、at all hours of the day
D、by means of reading and writing
【正确答案】：A
【题目解析】：原文中提到“Universities, colleges and schools use online distance learning environments. These are important for students who may be unable to attend classes for various reasons like illnesses or busy everyday schedules.” 这段话明确指出，大学、学院和学校使用在线远程学习环境，这对于因为各种原因（如疾病或繁忙的日常日程）无法到校上课的学生来说是很重要的。因此，可以推断出通过常规学习方式，学生需要到学校上课。 选项A“at school”与学校上课相符，是正确答案。 选项B“on their own”虽然在线学习是自主进行的，但这不是常规学习方式的描述。 选项C“at all hours of the day”虽然在线学习可能需要学生在一天中的任何时间学习，但这不是常规学习方式的普遍特征。 选项D“by means of reading and writing”是在线学习中常用的一种方式，但不是常规学习方式的主要特征。