问题补充:
A good teacher must be able to hold his students’ attention he reaches the end of the class.
A. when
B. after
C. until
D. unless
答案:
A. when
B. after
(答案→)C. until
D. unless
解析:考查连词辨析。A当…时;B在…后;C直到…才;D除非;句意:好的老师一定能够吸引教师的注意力,直到这节课结束。本句中前面句子的谓语动词hold his students’ attention是一个延续性动词,如果是短暂性动词,则使用not…until…;故C正确。