Jumping out of _____airplane at ten thousand feet is quite ____exciting experience

题目

Jumping out of _____airplane at ten thousand feet is quite ____exciting experience
A 不填/an
B an/an

答案

B
从10,000英尺高的飞机上跳出来时一项很刺激的经验
第一个an是和airplane搭配的,如果用airplanes也可以代替an airplane
An animal have to breath.
Animals have to breath.
第二个an就是意思,一个.