在此句中，the +单数可数名词，表示类别，不是the+adj. the+单数可数名词，表示的含义是一类，但是形式是单数，所以其谓语动词依然是用is。 后面的the student也是类别。 The teacher is responsible for the student's success...... =Teachers are responsible for students' success...... 注意：可数名词的复数也可以表示类别。 因此第二句中的They=Teachers They are only there ... =Teachers are only there ...
