问题
选择题
Catching _____ sight of their head teacher coming, the students fell into silence all of _____ sudden.
A．the; the
B．/; a
C．the; a
D．/; /
答案
答案：B
题目分析：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。