midstream的解释，在云词典中midstream是什么意思？

midstream

['mid'stri:m]
n.
河流正中, 中流

Although many of the board members saw that the president was ill equipped to handle the company's recession-related difficulties, they felt it best not to change horses in midstream.
虽然许多董事们认识到现在的董事长没有能力克服公司由于不景气而带来的种种困难，但是他们觉得最好不要中途换人。
It is very serious and important, Why do you change horses in midstream.
这是十分严肃而又重要的事。你为什么中途改变计划了？
The speaker stops in midstream, cough, then start up again.
演讲人中途停下来咳嗽，然後又继续讲。