完形填空(阅读以下材料 回答第51——65题)Many teachers believe that

完形填空(阅读以下材料，回答第51——65题)

Many teachers believe that the responsibilities for learning lie with the student._________(51) a long reading assignment is given,instructors expect students to be familiar with the_________(52) in the reading even if they do not discuss it in class or take an examination.The__________(53) student is considered to be one who is motivated（激励）to learn for the sake of_________(54),not the one interested only in getting high grades.Sometimes homework is returned________(55)brief written comments but without a grade.Even if a grade is not given,the student is_________(56) for learning the material assigned.When research is________(57),the professor expects the student to take it actively and to complete it with minimum guidance.It is the_________(58)responsibility to find books, magazines,and articles in the library.Professors do not have the time to explain _________(59)a university library works;they expect students,______(60)graduate students,to be able to exhaust the reference sources in the library.Professors will help students who need it,but_________(61)that their students should not be too dependent on them. In the United States professors have many other duties________(62)teaching,such as administrative or research work.________(63),the time that a professor can spend with student outside of class is_________(64).If a student has problems with classroom work,the student should either approach a professor during office hour_________(65)make an appointment.

_________(51)

A.If

B.Although

C.As

D.Since