Student participation(参与) in the classroom is not only accepted but also expected of the student in many courses．Some professors base part of the final grade on the student" s oral participation．Although there are formal lectures during which the student has a passive role (i．e．, listening and taking notes), many courses are organized around classroom discussions, student questions, and informal lectures．In graduate discussions the professor has a "manager" role and the students make presentations and lead discussions．The students do the actual teaching in these discussions． A professor" s teaching method is another factor (因素) that determines the degree and type of student participation．Some professors prefer to control discussion while others prefer to guide the class without controlling it．Many professors encourage students to question their ideas．Students who object to the professor" s point of view should be prepared to prove their positions． In the teaching of science and mathematics, the controlling mode of instruction is generally traditional ,with teachers presenting formal lectures and students taking notes．However, new educational trends have turned up in the humanities and social sciences in the past twenty years．Students in education, society, and history classes, for example, are often required to solve problems in groups, design projects, make presentations, and examine case studies．Since some college or university courses are"practical" rather than theoretical ,they pay more attention to "doing" for themselves． Which of the following sentences is true according to the passage?

B

事实细节题。第二段第二句指出，一些教授喜欢控制课堂讨论，而另一些教授则指导讨论。