They must be working because they have a lot of work to do yesterday.A. any momentB. at th

问题补充：

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

答案：

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。