These general principles left undetermined two important matters: " What is an effective blockade? "

这些一般原则留下了两个重要问题未确定：“什么是有效封锁？

It's been conducting military exercises to develop the capabilities that it would need for an effective blockade or an effective invasion.

它一直在进行军事演习， 以发展有效封锁或有效入侵所需的能力。