问题补充:
The pilot,(飞行员) whether or on purpose, made the plane do a sharp turn.(急转弯)
A. by accident
B. at times
C. suddenly
D. at once
答案:
(答案→)A. by accident
B. at times
C. suddenly
D. at once
解析:考查短语必须。by accident偶然;at times有时;at once立刻。根据句意:是偶然的或有目的的,故选A。