单项选择题
A．how well they perform in class B．how carefully they prepare their lessons C．how fluently they express themselves in class D．how hard they work before and in class
A．go over the lessons thoroughly B．understand required textbooks well C．do the reading assignments D．prepare an outline for discussion
A．try to please their students B．treat their' students as consumers C．understand their students well D．make sure their students understand