This morning traffic was by an accident outside the town hall.
A. held off
B. held up
C. held on
D. held over
网友回答
A. held off
(答案→)B. held up
C. held on
D. held over
解析：考查动词短语。句意:今天早上在市政大厅外交通为一事故所阻。hold off 抵制； hold up举起；阻挡；hold on不挂断电话，等一下；继续；hold
over延期；以…威胁; 结合句意可知选B。