Some aspects(方面) of a teacher’s job be tiring, and teachers often work at inconvenient hours.
A. can; must
B. may; can
C. can; have to
D. have to; must
网友回答
A. can; must
B. may; can
(答案→)C. can; have to
D. have to; must
解析：考查情态动词：第一空填can，表示：有客观的可能性，第二空填have to不得不.句意：老师工作的一些方面有可能令人疲倦，并且老师经常在不方便的时候工作。选C。