She felt completely during the vacation but now she has to go back to her work again. A. a

问题补充：

She felt completely during the vacation but now she has to go back to her work again.

A. at sea

B. at ease

C. at a loss

D. at risk

答案：

A. at sea

(答案→)B. at ease

C. at a loss

D. at risk

解析：考查介词短语。A=C茫然，不知多措；B舒适(地)，安逸(地)；D处于危险中；根据上下文句意可知B正确。句意：在假期中 她感觉很舒适，但是现在她又工作了。