Don’t all stand up together! , please.
A. Each at one time
B. One at a time
C. One by one time
D. One for each time
网友回答
A. Each at one time
(答案→)B. One at a time
C. One by one time
D. One for each time
解析:句意:不要都站起来,请每次站起一个。at a time一次,每次,at one time一度,曾经,所以选B。