the machine wouldn't work.can you try it again为什麽是选wouldn't而不是couldn't ?详情解释.

the machine wouldn't work.can you try it again为什麽是选wouldn't而不是couldn't ?详情解释.
the machine wouldn't work.can you try it again
为什麽是选wouldn't
而不是couldn't ?
详情解释.

the machine wouldn't work.can you try it again为什麽是选wouldn't而不是couldn't ?详情解释.
could表示有能力做什么事.

wouldn't表示的不是“将来不……”或“不愿……”，而是表示“拒绝”“不肯”“不能”，“怎么也不”，主语可以是人或物。
couldn 在一般句子表示的是一种能力（虚拟语气除外），主语是人。
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