问题
选择题
That was because the school bus was _________ by a thick fog.
A．broke off
B．held up
C．kept up
D．turned off
答案
B
题目分析：句意：那都是因为由于大雾校车被延误了。A. break off打断，终止C. keep up保持D. turn off 关掉电源等B. hold up 延误,阻挡，根据句意和动词短语的意思判断B最佳。
考点:考查动词短语的用法。