Catching sight of their head teacher ing, the students fell into silence all of sudden.
A. the; the
B. /; a
C. the; a
D. /; /
网友回答
A. the; the
(答案→)B. /; a
C. the; a
D. /; /
解析：考查冠词和固定搭配。此题可以使用排除法来做。catch sight of sth看见某物，是固定搭配，排除A、C；all of a sudden突然，相当于suddenly，是固定搭配，排除D，故选B。