Many teachers believe that the responsibilities for learning lie with the students.【C1】___

___a long reading assignment is given, instructors expect students to be familiar with the【C2】______in the reading even if they do not discuss it in class or take an examination. The【C3】______student is considered to be【C4】______who is motivated(激发)to learn for the sake of【C5】______, not the one interested only in get ting high grades. Sometimes homework is returned【C6】______brief written comments but without a grade. Even if a grade is not given, the student is【C7】______for learning the material assigned. When research is【C8】______, the professor expects the students to take it actively and complete it with【C9】______guidance. It is the【C10】______responsibility to find books, magazines, and articles in the library. Professors do not have the time to explain【C11】______a university library works; they expect students,【C12】______graduate students, to be able to exhaust the reference【C13】______in the library. Professors will help students who need it, but【C14】______that their students should not be【C15】______dependent on them. In the United States professors have many other duties【C16】______teaching, such as administrative or re search work.【C17】______, the time that a professor can spend with a student outside of class is【C18】______If a student has problems with classroom work, the student should either【C19】______a professor during office hours【C20】______make an appointment.

【C1】

A．If

B．Although

C．Because

D．Since