They must be working because they have a lot of work to do yesterday.
A. any moment
B. at the moment
C. just a moment
D. the moment
网友回答
A. any moment
(答案→)B. at the moment
C. just a moment
D. the moment
解析：句意：他们那时一定在工作，因为他们昨天有很多工作要做。any moment任何时候；at the moment 那时；just a moment 稍等一下；the moment（that）=as soon as从语境中可知，强调昨天那个时候，所以用at the moment。故选B。
考点: 考查名词短语的用法。