It was so quiet in the classroom that a
题型:选择题
问题:
It was so quiet in the classroom that a needle _________ to drop onto the floor. [ ]
A. could hear
B. was to be heard
C. could have been heard
D. must be heard
It was so quiet in the classroom that a needle _________ to drop onto the floor. [ ]
A. could hear
B. was to be heard
C. could have been heard
D. must be heard