at some instant

• 在某一瞬间

at some instant的用法和样例：

例句

1. The full line gives the shape of the surface at the instant show.
   实线表示某一瞬间液体表面的形状。
2. If the circulation vanishes at one instant of time, it must vanish for all times.
   只要环量在某一瞬间为零，它就必须永远为零。