改错,找出句子中带括号部分有错误的一项,并改正.(英语)

问题描述:

改错,找出句子中带括号部分有错误的一项,并改正.(英语)
It (flies) at about eleven (kilometres) (one second).

It (flies) at about eleven (kilometres) (one second).
one second >>>>a second
或者per second 都是每秒的意思