The blood vessels may leak fluid, which distorts vision...

血管可能会渗漏，造成视力模糊。

Make sure that you drink plenty of fluids.

务必保证足够的水分摄入。

The forehand stroke should be fluid and well balanced.

正手击球应该保证动作流畅和平稳。

...long, fluid dresses.

线条优雅流畅的长裙

The situation is extremely fluid and it can be changing from day to day.

情况极不稳定，每天都有可能变化。