第二节 语法填空(共10小题；每小题1．5分，满分15分)

阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词语的正确形式填空，并将答案填写在答卷标号为31-40的相应位置上。

Many teachers believe that the responsibilities for learning lie with the student.  31     a long reading assignment is given, instructors expect students to be familiar  32     information in the reading even if they do not discuss it in class or take an examination. The ideal student is considered to be   33   who is motivated to learn for the sake of learning, not the one interested only in getting high grades. Sometimes homework is returned with brief   34    (write) comments but without a grade.Even if a grade is not given, the student is responsible for learning the material assigned. When research   35   (assign), the professor expects the student to take it actively and to complete it with minimum   36    (guide). It is the student's responsibility to find books, magazines, and articles in the library. Professors do not have the time to explain   37    a university library works; they expect students,particularly graduate students, to be able to exhaust the reference origins in the library.Professors will help students who need it, but prefer that their students should not be too dependent on them. In the United States, professors have many other duties   38 teaching, such as administrative or research work. Therefore, the time   39    a professor can spend with a student outside of class is limited. If  40    student has problems with classroom work, the student should either approach a professor during either office hours or make an appointment.

磁悬浮列车是一种利用磁极间的（）运作的高科技交通工具。

A、电磁体

B、引导磁体

C、吸引力和排斥力