Nobody can do two things well __ .A.at one time B.at once C.one time D.
问题描述：
Nobody can do two things well __ .A.at one time B.at once C.one time D.
Nobody can do two things well __ .A.at one time B.at once C.one time D.once
B正确,但为什么不选A呢?A不也是有“同时”的意思吗?
答
at one time意思是一度,从前,同时的意思不明显,只有答案B是有同时的意思,也最符合句意