The pilot (飞行员) whether or on purpose made the plane do a sharp turn.(急转弯)A. by accident

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。