问题
单项选择题
The discussion was so prolonged and exhausting that______ the speakers stopped for refreshments.
A．at large
B．at intervals
C．at ease
D．at random
答案
参考答案：B
解析： at intervals不时，时时。A．at large逍遥法外，未被捕获；C．at ease自在，合适；D．at random任意，随机。