虚拟语气里有would 和could,什么时候用would ,什么时候用couldhow to motivate criminals to learn would be a problem * officers have to save.这里的would 可以替换could吗how to motivate criminals to learn是一个主语从句吧,to learn作主语从句的什么成分. * officers have to save是个定语从句,为什么把that 和which省略了

虚拟语气里有would 和could,什么时候用would ,什么时候用could
how to motivate criminals to learn would be a problem * officers have to save.
这里的would 可以替换could吗
how to motivate criminals to learn是一个主语从句吧,to learn作主语从句的什么成分.
* officers have to save是个定语从句,为什么把that 和which省略了